<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:01a064cd-b47b-7afd-b94c-c6b4974dacf9,g:6ddd3e9c-6c31-488c-8ab3-faea0f98a0dc-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.innventure.com/role/ConsolidatedBalanceSheets" xlink:type="simple" xlink:href="innv-20260930.xsd#ConsolidatedBalanceSheets"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/ConsolidatedBalanceSheets" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_01a064cd-b631-7aeb-a097-bd2ec8b029c0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_01a064cd-b631-76ad-a6da-9e4b1eddda1c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b631-7aeb-a097-bd2ec8b029c0" xlink:to="loc_us-gaap_StatementTable_01a064cd-b631-76ad-a6da-9e4b1eddda1c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_01a064cd-b631-7b65-a93e-8e9b2a1d8450" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_01a064cd-b631-76ad-a6da-9e4b1eddda1c" xlink:to="loc_us-gaap_StatementClassOfStockAxis_01a064cd-b631-7b65-a93e-8e9b2a1d8450" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_01a064cd-b631-7b65-a93e-8e9b2a1d8450_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_01a064cd-b631-7b65-a93e-8e9b2a1d8450" xlink:to="loc_us-gaap_ClassOfStockDomain_01a064cd-b631-7b65-a93e-8e9b2a1d8450_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_01a064cd-b631-7eef-97f6-a5bf1138a419" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_01a064cd-b631-7b65-a93e-8e9b2a1d8450" xlink:to="loc_us-gaap_ClassOfStockDomain_01a064cd-b631-7eef-97f6-a5bf1138a419" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesBPreferredStockMember_01a064cd-b631-739e-b252-b419fd502193" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeriesBPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_01a064cd-b631-7eef-97f6-a5bf1138a419" xlink:to="loc_us-gaap_SeriesBPreferredStockMember_01a064cd-b631-739e-b252-b419fd502193" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesCPreferredStockMember_01a064cd-b631-7938-b156-968eee2d8fc0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeriesCPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_01a064cd-b631-7eef-97f6-a5bf1138a419" xlink:to="loc_us-gaap_SeriesCPreferredStockMember_01a064cd-b631-7938-b156-968eee2d8fc0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_01a064cd-b631-7243-a08c-d41a5e4acaf1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b631-7aeb-a097-bd2ec8b029c0" xlink:to="loc_us-gaap_AssetsAbstract_01a064cd-b631-7243-a08c-d41a5e4acaf1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_01a064cd-b631-7553-9301-b6c8a8279b3b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_01a064cd-b631-7243-a08c-d41a5e4acaf1" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_01a064cd-b631-7553-9301-b6c8a8279b3b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashCurrent_01a064cd-b631-7bcf-924e-d45764dc9b8c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_01a064cd-b631-7243-a08c-d41a5e4acaf1" xlink:to="loc_us-gaap_RestrictedCashCurrent_01a064cd-b631-7bcf-924e-d45764dc9b8c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_01a064cd-b631-7047-90c3-85c557d805dc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_01a064cd-b631-7243-a08c-d41a5e4acaf1" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_01a064cd-b631-7047-90c3-85c557d805dc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherReceivablesNetCurrent_01a064cd-b631-780f-8712-36f7bb5972f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherReceivablesNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_01a064cd-b631-7243-a08c-d41a5e4acaf1" xlink:to="loc_us-gaap_OtherReceivablesNetCurrent_01a064cd-b631-780f-8712-36f7bb5972f2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet_01a064cd-b631-7d52-afa6-eef75cd894f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InventoryNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_01a064cd-b631-7243-a08c-d41a5e4acaf1" xlink:to="loc_us-gaap_InventoryNet_01a064cd-b631-7d52-afa6-eef75cd894f3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_01a064cd-b631-79a2-af4e-939190ab0f2a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_01a064cd-b631-7243-a08c-d41a5e4acaf1" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_01a064cd-b631-79a2-af4e-939190ab0f2a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_01a064cd-b631-7f8b-b5c0-6208d423a4ce" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_01a064cd-b631-7243-a08c-d41a5e4acaf1" xlink:to="loc_us-gaap_AssetsCurrent_01a064cd-b631-7f8b-b5c0-6208d423a4ce" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermInvestments_01a064cd-b631-7991-9695-00513100e4ac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_01a064cd-b631-7243-a08c-d41a5e4acaf1" xlink:to="loc_us-gaap_LongTermInvestments_01a064cd-b631-7991-9695-00513100e4ac" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_01a064cd-b631-7926-bae8-65fb6b5693dd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_01a064cd-b631-7243-a08c-d41a5e4acaf1" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_01a064cd-b631-7926-bae8-65fb6b5693dd" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_01a064cd-b631-7722-ba21-74502ae2a093" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_01a064cd-b631-7243-a08c-d41a5e4acaf1" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_01a064cd-b631-7722-ba21-74502ae2a093" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_01a064cd-b631-7860-ab4f-551a73d8934b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_01a064cd-b631-7243-a08c-d41a5e4acaf1" xlink:to="loc_us-gaap_Goodwill_01a064cd-b631-7860-ab4f-551a73d8934b" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_01a064cd-b631-7efa-b816-ad60c23b21be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_01a064cd-b631-7243-a08c-d41a5e4acaf1" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_01a064cd-b631-7efa-b816-ad60c23b21be" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_01a064cd-b631-7b32-95b7-6d76063f0f7b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_01a064cd-b631-7243-a08c-d41a5e4acaf1" xlink:to="loc_us-gaap_Assets_01a064cd-b631-7b32-95b7-6d76063f0f7b" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b631-7aeb-a097-bd2ec8b029c0" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_01a064cd-b631-7ba5-b4c5-f2921ebeffed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_AccountsPayableCurrent_01a064cd-b631-7ba5-b4c5-f2921ebeffed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedEmployeeBenefitsCurrent_01a064cd-b631-7d2f-922b-ce31cb790d4c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedEmployeeBenefitsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_AccruedEmployeeBenefitsCurrent_01a064cd-b631-7d2f-922b-ce31cb790d4c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAccruedLiabilitiesCurrent_01a064cd-b631-7f34-8f61-3dc910c561da" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_OtherAccruedLiabilitiesCurrent_01a064cd-b631-7f34-8f61-3dc910c561da" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_01a064cd-b631-7759-b444-ed2d38ffc91d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_01a064cd-b631-7759-b444-ed2d38ffc91d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNotesPayableCurrent_01a064cd-b631-70a3-b308-4752f6f76326" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNotesPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_OtherNotesPayableCurrent_01a064cd-b631-70a3-b308-4752f6f76326" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtCurrent_01a064cd-b631-7f0e-a77b-a72559a1a30e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleDebtCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_ConvertibleDebtCurrent_01a064cd-b631-7f0e-a77b-a72559a1a30e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleNotesPayableCurrent_01a064cd-b631-702b-aa60-86afdd48be15" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleNotesPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_ConvertibleNotesPayableCurrent_01a064cd-b631-702b-aa60-86afdd48be15" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_PatentInstallmentPayableCurrent_01a064cd-b631-7d6b-8b34-d458e386924f" xlink:href="innv-20260930.xsd#innv_PatentInstallmentPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_innv_PatentInstallmentPayableCurrent_01a064cd-b631-7d6b-8b34-d458e386924f" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_EquityIssuanceLiabilityCurrent_01a064cd-b631-7df7-8ae8-dea2105b2dbf" xlink:href="innv-20260930.xsd#innv_EquityIssuanceLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_innv_EquityIssuanceLiabilityCurrent_01a064cd-b631-7df7-8ae8-dea2105b2dbf" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantsAndRightsOutstanding_01a064cd-b631-7437-a0ba-ca82cf3e5912" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WarrantsAndRightsOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_WarrantsAndRightsOutstanding_01a064cd-b631-7437-a0ba-ca82cf3e5912" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxesPayableCurrent_01a064cd-b631-7437-8d6c-73dee944144e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TaxesPayableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_TaxesPayableCurrent_01a064cd-b631-7437-8d6c-73dee944144e" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCompensationShareBasedArrangementsLiabilityCurrent_01a1b2a5-c448-7265-ac31-5397d5cfe927" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredCompensationShareBasedArrangementsLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_DeferredCompensationShareBasedArrangementsLiabilityCurrent_01a1b2a5-c448-7265-ac31-5397d5cfe927" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesCurrent_01a064cd-b631-7144-9a55-c9b21b67da71" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_OtherLiabilitiesCurrent_01a064cd-b631-7144-9a55-c9b21b67da71" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_01a064cd-b631-7d6a-a933-e347f8793b58" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_LiabilitiesCurrent_01a064cd-b631-7d6a-a933-e347f8793b58" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLongTermNotesPayable_01a064cd-b631-7ac1-b0d4-35ba885ae098" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLongTermNotesPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_OtherLongTermNotesPayable_01a064cd-b631-7ac1-b0d4-35ba885ae098" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityNoncurrent_01a064cd-b631-77af-a327-7cb4bf4487ee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationContingentConsiderationLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiabilityNoncurrent_01a064cd-b631-77af-a327-7cb4bf4487ee" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCompensationSharebasedArrangementsLiabilityClassifiedNoncurrent_01a064cd-b631-7920-b6bc-4ae7b2b58ded" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredCompensationSharebasedArrangementsLiabilityClassifiedNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_DeferredCompensationSharebasedArrangementsLiabilityClassifiedNoncurrent_01a064cd-b631-7920-b6bc-4ae7b2b58ded" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_PatentInstallmentPayableNoncurrent_01a064cd-b631-742d-9479-e5b98815e93c" xlink:href="innv-20260930.xsd#innv_PatentInstallmentPayableNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_innv_PatentInstallmentPayableNoncurrent_01a064cd-b631-742d-9479-e5b98815e93c" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_01a064cd-b631-7d89-a642-fe1f02c47a86" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_DeferredIncomeTaxLiabilitiesNet_01a064cd-b631-7d89-a642-fe1f02c47a86" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_01a064cd-b631-7a80-8781-a6d6e369ea61" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_01a064cd-b631-7a80-8781-a6d6e369ea61" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_01a064cd-b631-7b9f-9645-6db5ff065210" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_Liabilities_01a064cd-b631-7b9f-9645-6db5ff065210" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_01a064cd-b631-7edc-a018-222d64b4cca2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_CommitmentsAndContingencies_01a064cd-b631-7edc-a018-222d64b4cca2" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityAbstract_01a064cd-b631-7e1a-ab0f-b3116e523cf0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_StockholdersEquityAbstract_01a064cd-b631-7e1a-ab0f-b3116e523cf0" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockValue_01a064cd-b631-73d4-8cfb-ab899ba5e066" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_01a064cd-b631-7e1a-ab0f-b3116e523cf0" xlink:to="loc_us-gaap_PreferredStockValue_01a064cd-b631-73d4-8cfb-ab899ba5e066" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_01a064cd-b631-7c44-b214-771b42e76e48" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_01a064cd-b631-7e1a-ab0f-b3116e523cf0" xlink:to="loc_us-gaap_CommonStockValue_01a064cd-b631-7c44-b214-771b42e76e48" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapital_01a064cd-b631-74f3-855e-106d5ed31334" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_01a064cd-b631-7e1a-ab0f-b3116e523cf0" xlink:to="loc_us-gaap_AdditionalPaidInCapital_01a064cd-b631-74f3-855e-106d5ed31334" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_01a064cd-b631-7f8d-9a49-023edf0d5dcb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_01a064cd-b631-7e1a-ab0f-b3116e523cf0" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_01a064cd-b631-7f8d-9a49-023edf0d5dcb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_01a064cd-b631-7000-9339-67f72c541aa3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_01a064cd-b631-7e1a-ab0f-b3116e523cf0" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_01a064cd-b631-7000-9339-67f72c541aa3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_01a064cd-b631-7c6d-89a8-69bd18565e11" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_01a064cd-b631-7e1a-ab0f-b3116e523cf0" xlink:to="loc_us-gaap_StockholdersEquity_01a064cd-b631-7c6d-89a8-69bd18565e11" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterest_01a064cd-b631-7d0b-9ff8-d634de2f1caa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MinorityInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_01a064cd-b631-7e1a-ab0f-b3116e523cf0" xlink:to="loc_us-gaap_MinorityInterest_01a064cd-b631-7d0b-9ff8-d634de2f1caa" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_01a064cd-b631-7128-b1f4-14349d280caa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_01a064cd-b631-7e1a-ab0f-b3116e523cf0" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_01a064cd-b631-7128-b1f4-14349d280caa" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_01a064cd-b631-7a3c-a971-c6f362486d7a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_01a064cd-b631-7a6f-abe6-712d6dc7b21b" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_01a064cd-b631-7a3c-a971-c6f362486d7a" xlink:type="arc" order="24"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="simple" xlink:href="innv-20260930.xsd#ConsolidatedBalanceSheetsParenthetical"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_01a064cd-b632-7c70-b1bc-d2b16a10abb9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_01a064cd-b632-7924-9ae2-6b917e4abf08" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-7c70-b1bc-d2b16a10abb9" xlink:to="loc_us-gaap_StatementTable_01a064cd-b632-7924-9ae2-6b917e4abf08" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_01a064cd-b632-7f0e-8550-64ba8f447fe2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_01a064cd-b632-7924-9ae2-6b917e4abf08" xlink:to="loc_us-gaap_StatementClassOfStockAxis_01a064cd-b632-7f0e-8550-64ba8f447fe2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_01a064cd-b632-7f0e-8550-64ba8f447fe2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_01a064cd-b632-7f0e-8550-64ba8f447fe2" xlink:to="loc_us-gaap_ClassOfStockDomain_01a064cd-b632-7f0e-8550-64ba8f447fe2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_01a064cd-b632-7de5-9348-d743487e9c7b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_01a064cd-b632-7f0e-8550-64ba8f447fe2" xlink:to="loc_us-gaap_ClassOfStockDomain_01a064cd-b632-7de5-9348-d743487e9c7b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesBPreferredStockMember_01a064cd-b632-7eb0-ae9d-c6efa45785ef" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeriesBPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_01a064cd-b632-7de5-9348-d743487e9c7b" xlink:to="loc_us-gaap_SeriesBPreferredStockMember_01a064cd-b632-7eb0-ae9d-c6efa45785ef" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesCPreferredStockMember_01a064cd-b632-72d3-97ab-c58bdd5f899d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeriesCPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_01a064cd-b632-7de5-9348-d743487e9c7b" xlink:to="loc_us-gaap_SeriesCPreferredStockMember_01a064cd-b632-72d3-97ab-c58bdd5f899d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_01a064cd-b632-70e7-91ec-0b9263de235a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-7c70-b1bc-d2b16a10abb9" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_01a064cd-b632-70e7-91ec-0b9263de235a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_01a064cd-b632-77c5-bd96-01322cf2b1f7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-7c70-b1bc-d2b16a10abb9" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_01a064cd-b632-77c5-bd96-01322cf2b1f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesIssued_01a064cd-b632-7adc-af83-10d9c849779b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-7c70-b1bc-d2b16a10abb9" xlink:to="loc_us-gaap_PreferredStockSharesIssued_01a064cd-b632-7adc-af83-10d9c849779b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_01a064cd-b632-72d3-bee6-f862dea3a62b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-7c70-b1bc-d2b16a10abb9" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_01a064cd-b632-72d3-bee6-f862dea3a62b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_01a064cd-b632-702f-a5d7-af212ee4093c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-7c70-b1bc-d2b16a10abb9" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_01a064cd-b632-702f-a5d7-af212ee4093c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_01a064cd-b632-70d9-b1e8-b96f795dfc27" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-7c70-b1bc-d2b16a10abb9" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_01a064cd-b632-70d9-b1e8-b96f795dfc27" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_01a064cd-b632-7e95-9934-a094e47d1b67" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-7c70-b1bc-d2b16a10abb9" xlink:to="loc_us-gaap_CommonStockSharesIssued_01a064cd-b632-7e95-9934-a094e47d1b67" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_01a064cd-b632-77ae-aeee-a50b76e2ee7c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-7c70-b1bc-d2b16a10abb9" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_01a064cd-b632-77ae-aeee-a50b76e2ee7c" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/ConsolidatedStatementsofOperationsandComprehensiveIncomeLoss" xlink:type="simple" xlink:href="innv-20260930.xsd#ConsolidatedStatementsofOperationsandComprehensiveIncomeLoss"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/ConsolidatedStatementsofOperationsandComprehensiveIncomeLoss" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_01a064cd-b632-79f1-85f6-42bd44331734" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_01a064cd-b632-7e49-bb89-23a2ce82a255" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-79f1-85f6-42bd44331734" xlink:to="loc_us-gaap_StatementTable_01a064cd-b632-7e49-bb89-23a2ce82a255" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a064cd-b632-7e48-83a5-dd8609ca8582" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_01a064cd-b632-7e49-bb89-23a2ce82a255" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a064cd-b632-7e48-83a5-dd8609ca8582" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a064cd-b632-7e48-83a5-dd8609ca8582_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a064cd-b632-7e48-83a5-dd8609ca8582" xlink:to="loc_us-gaap_RelatedPartyDomain_01a064cd-b632-7e48-83a5-dd8609ca8582_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a064cd-b632-7107-9d0f-dfb75c283c70" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a064cd-b632-7e48-83a5-dd8609ca8582" xlink:to="loc_us-gaap_RelatedPartyDomain_01a064cd-b632-7107-9d0f-dfb75c283c70" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonrelatedPartyMember_01a064cd-b632-7488-a31e-a54aa06f7551" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonrelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_01a064cd-b632-7107-9d0f-dfb75c283c70" xlink:to="loc_us-gaap_NonrelatedPartyMember_01a064cd-b632-7488-a31e-a54aa06f7551" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_01a064cd-b632-7cb5-8ed2-667db4773221" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_01a064cd-b632-7107-9d0f-dfb75c283c70" xlink:to="loc_us-gaap_RelatedPartyMember_01a064cd-b632-7cb5-8ed2-667db4773221" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_01a064cd-b632-7a17-a2bd-f1ce2d18d238" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-79f1-85f6-42bd44331734" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_01a064cd-b632-7a17-a2bd-f1ce2d18d238" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpensesAbstract_01a064cd-b632-7ca5-a5cf-65fca8cb67f9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-79f1-85f6-42bd44331734" xlink:to="loc_us-gaap_OperatingExpensesAbstract_01a064cd-b632-7ca5-a5cf-65fca8cb67f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_01a064cd-b632-7fc1-8860-f8811b06e4bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_01a064cd-b632-7ca5-a5cf-65fca8cb67f9" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_01a064cd-b632-7fc1-8860-f8811b06e4bc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_01a064cd-b632-719a-9691-41a94ca58762" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_01a064cd-b632-7ca5-a5cf-65fca8cb67f9" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_01a064cd-b632-719a-9691-41a94ca58762" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingAndMarketingExpense_01a064cd-b632-794a-828e-1f2c9f770c87" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SellingAndMarketingExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_01a064cd-b632-7ca5-a5cf-65fca8cb67f9" xlink:to="loc_us-gaap_SellingAndMarketingExpense_01a064cd-b632-794a-828e-1f2c9f770c87" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_01a064cd-b632-7056-adf9-a72634db43ad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_01a064cd-b632-7ca5-a5cf-65fca8cb67f9" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_01a064cd-b632-7056-adf9-a72634db43ad" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_01a064cd-b632-7928-b415-5106e5475d38" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_01a064cd-b632-7ca5-a5cf-65fca8cb67f9" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_01a064cd-b632-7928-b415-5106e5475d38" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpenses_01a064cd-b632-7116-976c-c13ee8def92c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostsAndExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_01a064cd-b632-7ca5-a5cf-65fca8cb67f9" xlink:to="loc_us-gaap_CostsAndExpenses_01a064cd-b632-7116-976c-c13ee8def92c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_01a064cd-b632-7834-ace1-56c302c481f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-79f1-85f6-42bd44331734" xlink:to="loc_us-gaap_OperatingIncomeLoss_01a064cd-b632-7834-ace1-56c302c481f8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpenseAbstract_01a064cd-b632-7645-8f0d-bbfa435839ce" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonoperatingIncomeExpenseAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-79f1-85f6-42bd44331734" xlink:to="loc_us-gaap_NonoperatingIncomeExpenseAbstract_01a064cd-b632-7645-8f0d-bbfa435839ce" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNonoperatingNet_01a064cd-b632-707d-b497-d5406d6d5fc3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestIncomeExpenseNonoperatingNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_01a064cd-b632-7645-8f0d-bbfa435839ce" xlink:to="loc_us-gaap_InterestIncomeExpenseNonoperatingNet_01a064cd-b632-707d-b497-d5406d6d5fc3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnInvestments_01a064cd-b632-7bdd-b3f7-d7fcd481d7ad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_01a064cd-b632-7645-8f0d-bbfa435839ce" xlink:to="loc_us-gaap_GainLossOnInvestments_01a064cd-b632-7bdd-b3f7-d7fcd481d7ad" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_UnrealizedGainLossOnFinancialLiabilities_01a064cd-b632-754c-983c-8c7ebb4d47f8" xlink:href="innv-20260930.xsd#innv_UnrealizedGainLossOnFinancialLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_01a064cd-b632-7645-8f0d-bbfa435839ce" xlink:to="loc_innv_UnrealizedGainLossOnFinancialLiabilities_01a064cd-b632-754c-983c-8c7ebb4d47f8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_01a064cd-b632-74e9-84d9-d3ed79652393" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_01a064cd-b632-7645-8f0d-bbfa435839ce" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_01a064cd-b632-74e9-84d9-d3ed79652393" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleRealizedGain_01a064cd-b632-737b-833d-6f93d3efc3f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleRealizedGain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_01a064cd-b632-7645-8f0d-bbfa435839ce" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleRealizedGain_01a064cd-b632-737b-833d-6f93d3efc3f5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_01a064cd-b632-71a2-bd76-958b1bdbe087" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_01a064cd-b632-7645-8f0d-bbfa435839ce" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_01a064cd-b632-71a2-bd76-958b1bdbe087" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_01a064cd-b632-7c95-af9c-87ba2e94f62c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_01a064cd-b632-7645-8f0d-bbfa435839ce" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_01a064cd-b632-7c95-af9c-87ba2e94f62c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_01a064cd-b632-7005-84d6-6167d1639d7b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NonoperatingIncomeExpenseAbstract_01a064cd-b632-7645-8f0d-bbfa435839ce" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_01a064cd-b632-7005-84d6-6167d1639d7b" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_01a064cd-b632-70b4-bb29-4115a6ae2609" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-79f1-85f6-42bd44331734" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_01a064cd-b632-70b4-bb29-4115a6ae2609" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_01a064cd-b632-7ce1-bf4b-e28fe1605856" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-79f1-85f6-42bd44331734" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_01a064cd-b632-7ce1-bf4b-e28fe1605856" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_01a064cd-b632-7886-b9ce-d1aca89c3ebd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-79f1-85f6-42bd44331734" xlink:to="loc_us-gaap_ProfitLoss_01a064cd-b632-7886-b9ce-d1aca89c3ebd" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestInNetIncomeLossOfConsolidatedEntitiesAbstract_01a064cd-b632-7b68-a3e6-59678c168dc9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MinorityInterestInNetIncomeLossOfConsolidatedEntitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-79f1-85f6-42bd44331734" xlink:to="loc_us-gaap_MinorityInterestInNetIncomeLossOfConsolidatedEntitiesAbstract_01a064cd-b632-7b68-a3e6-59678c168dc9" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_01a064cd-b632-75d8-b04b-c0f42aa75762" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MinorityInterestInNetIncomeLossOfConsolidatedEntitiesAbstract_01a064cd-b632-7b68-a3e6-59678c168dc9" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_01a064cd-b632-75d8-b04b-c0f42aa75762" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_01a064cd-b632-72e5-a641-7e4e3bb8ce38" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-79f1-85f6-42bd44331734" xlink:to="loc_us-gaap_NetIncomeLoss_01a064cd-b632-72e5-a641-7e4e3bb8ce38" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_01a064cd-b632-7d16-8172-ae313cf4763c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-79f1-85f6-42bd44331734" xlink:to="loc_us-gaap_EarningsPerShareBasic_01a064cd-b632-7d16-8172-ae313cf4763c" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_01a064cd-b632-7e92-a622-66b5c9baf571" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-79f1-85f6-42bd44331734" xlink:to="loc_us-gaap_EarningsPerShareDiluted_01a064cd-b632-7e92-a622-66b5c9baf571" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_01a064cd-b632-7197-969b-75bde9fa7dfc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-79f1-85f6-42bd44331734" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_01a064cd-b632-7197-969b-75bde9fa7dfc" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_01a064cd-b632-795d-976f-0e7690f363d1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-79f1-85f6-42bd44331734" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_01a064cd-b632-795d-976f-0e7690f363d1" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_01a064cd-b632-7443-a1cb-5cfc78dcf38f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-79f1-85f6-42bd44331734" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_01a064cd-b632-7443-a1cb-5cfc78dcf38f" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_01a064cd-b632-7861-8d5d-2b9feaf45270" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_01a064cd-b632-7443-a1cb-5cfc78dcf38f" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_01a064cd-b632-7861-8d5d-2b9feaf45270" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_01a1b28b-cf38-7fc3-89da-037e8bc51ffd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_01a064cd-b632-7443-a1cb-5cfc78dcf38f" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_01a1b28b-cf38-7fc3-89da-037e8bc51ffd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAociForInvestmentTransferredFromAvailableForSaleToEquityMethodBeforeTax_01a1cb29-c8b6-724e-9870-1a156e14e012" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAociForInvestmentTransferredFromAvailableForSaleToEquityMethodBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_01a064cd-b632-7443-a1cb-5cfc78dcf38f" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAociForInvestmentTransferredFromAvailableForSaleToEquityMethodBeforeTax_01a1cb29-c8b6-724e-9870-1a156e14e012" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_01a064cd-b632-7ff8-b5e4-04635db52271" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParentAbstract_01a064cd-b632-7443-a1cb-5cfc78dcf38f" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_01a064cd-b632-7ff8-b5e4-04635db52271" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_01a064cd-b632-7635-a138-2b99070b106c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-79f1-85f6-42bd44331734" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest_01a064cd-b632-7635-a138-2b99070b106c" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest_01a064cd-b632-7432-b3f6-f3f7b9310b9f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-79f1-85f6-42bd44331734" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest_01a064cd-b632-7432-b3f6-f3f7b9310b9f" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_01a064cd-b632-745f-bfae-6191850e2609" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-79f1-85f6-42bd44331734" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_01a064cd-b632-745f-bfae-6191850e2609" xlink:type="arc" order="16"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/ConsolidatedStatementsofChangesinMezzanineandStockholdersEquityDeficit" xlink:type="simple" xlink:href="innv-20260930.xsd#ConsolidatedStatementsofChangesinMezzanineandStockholdersEquityDeficit"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/ConsolidatedStatementsofChangesinMezzanineandStockholdersEquityDeficit" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_01a064cd-b632-78c5-9b8d-8607425cba43" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_01a064cd-b632-74f0-81c2-9a6919196460" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-78c5-9b8d-8607425cba43" xlink:to="loc_us-gaap_StatementTable_01a064cd-b632-74f0-81c2-9a6919196460" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_01a064cd-b632-7bba-a30c-f95da1db0700" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_01a064cd-b632-74f0-81c2-9a6919196460" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_01a064cd-b632-7bba-a30c-f95da1db0700" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_01a064cd-b632-7bba-a30c-f95da1db0700_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_01a064cd-b632-7bba-a30c-f95da1db0700" xlink:to="loc_us-gaap_EquityComponentDomain_01a064cd-b632-7bba-a30c-f95da1db0700_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_01a064cd-b632-73af-8256-ec518778397a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_01a064cd-b632-7bba-a30c-f95da1db0700" xlink:to="loc_us-gaap_EquityComponentDomain_01a064cd-b632-73af-8256-ec518778397a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockMember_01a064cd-b632-761b-9074-a9efb9f90a15" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01a064cd-b632-73af-8256-ec518778397a" xlink:to="loc_us-gaap_PreferredStockMember_01a064cd-b632-761b-9074-a9efb9f90a15" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_01a064cd-b632-78d1-a133-aca8322f037b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01a064cd-b632-73af-8256-ec518778397a" xlink:to="loc_us-gaap_CommonStockMember_01a064cd-b632-78d1-a133-aca8322f037b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_01a064cd-b632-7fdb-9172-f4846ee71bc8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01a064cd-b632-73af-8256-ec518778397a" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_01a064cd-b632-7fdb-9172-f4846ee71bc8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_01a064cd-b632-7b28-b7b9-6238cecde9d6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01a064cd-b632-73af-8256-ec518778397a" xlink:to="loc_us-gaap_RetainedEarningsMember_01a064cd-b632-7b28-b7b9-6238cecde9d6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_01a064cd-b632-7dc3-84ab-782c380a0281" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01a064cd-b632-73af-8256-ec518778397a" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_01a064cd-b632-7dc3-84ab-782c380a0281" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_01a064cd-b632-7d90-a261-0b7501970a37" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01a064cd-b632-73af-8256-ec518778397a" xlink:to="loc_us-gaap_NoncontrollingInterestMember_01a064cd-b632-7d90-a261-0b7501970a37" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_01a064cd-b632-7936-b62f-328f1957da59" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_01a064cd-b632-74f0-81c2-9a6919196460" xlink:to="loc_us-gaap_StatementClassOfStockAxis_01a064cd-b632-7936-b62f-328f1957da59" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_01a064cd-b632-7936-b62f-328f1957da59_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_01a064cd-b632-7936-b62f-328f1957da59" xlink:to="loc_us-gaap_ClassOfStockDomain_01a064cd-b632-7936-b62f-328f1957da59_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_01a064cd-b632-71d6-84a3-293390bc7b37" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_01a064cd-b632-7936-b62f-328f1957da59" xlink:to="loc_us-gaap_ClassOfStockDomain_01a064cd-b632-71d6-84a3-293390bc7b37" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesBPreferredStockMember_01a064cd-b632-7383-9718-05b579fdf0a0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeriesBPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_01a064cd-b632-71d6-84a3-293390bc7b37" xlink:to="loc_us-gaap_SeriesBPreferredStockMember_01a064cd-b632-7383-9718-05b579fdf0a0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesCPreferredStockMember_01a064cd-b632-793b-90dd-8c918965db06" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeriesCPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_01a064cd-b632-71d6-84a3-293390bc7b37" xlink:to="loc_us-gaap_SeriesCPreferredStockMember_01a064cd-b632-793b-90dd-8c918965db06" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConversionOfStockByUniqueDescriptionAxis_01a064cd-b632-786d-959b-caf327587d5f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConversionOfStockByUniqueDescriptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_01a064cd-b632-74f0-81c2-9a6919196460" xlink:to="loc_us-gaap_ConversionOfStockByUniqueDescriptionAxis_01a064cd-b632-786d-959b-caf327587d5f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConversionOfStockNameDomain_01a064cd-b632-786d-959b-caf327587d5f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConversionOfStockNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConversionOfStockByUniqueDescriptionAxis_01a064cd-b632-786d-959b-caf327587d5f" xlink:to="loc_us-gaap_ConversionOfStockNameDomain_01a064cd-b632-786d-959b-caf327587d5f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConversionOfStockNameDomain_01a064cd-b632-74ce-a7d6-be43cf521ca1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConversionOfStockNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConversionOfStockByUniqueDescriptionAxis_01a064cd-b632-786d-959b-caf327587d5f" xlink:to="loc_us-gaap_ConversionOfStockNameDomain_01a064cd-b632-74ce-a7d6-be43cf521ca1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ConversionToCommonStockMember_01a064cd-b632-72c7-8dd4-a607e9790e13" xlink:href="innv-20260930.xsd#innv_ConversionToCommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConversionOfStockNameDomain_01a064cd-b632-74ce-a7d6-be43cf521ca1" xlink:to="loc_innv_ConversionToCommonStockMember_01a064cd-b632-72c7-8dd4-a607e9790e13" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ConversionOfTemporaryToPermanentEquityMember_01a064cd-b632-7cea-aa61-08115aa36e7d" xlink:href="innv-20260930.xsd#innv_ConversionOfTemporaryToPermanentEquityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConversionOfStockNameDomain_01a064cd-b632-74ce-a7d6-be43cf521ca1" xlink:to="loc_innv_ConversionOfTemporaryToPermanentEquityMember_01a064cd-b632-7cea-aa61-08115aa36e7d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-78c5-9b8d-8607425cba43" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_01a064cd-b632-7749-8b80-9748e5c0fb31" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_01a064cd-b632-7749-8b80-9748e5c0fb31" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_01a064cd-b632-72ec-93ff-7468cc837324" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_01a064cd-b632-72ec-93ff-7468cc837324" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_01a064cd-b632-79f7-8ebd-b33950d5ea72" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_01a064cd-b632-79f7-8ebd-b33950d5ea72" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_01a064cd-b632-7151-be4b-a41d54014082" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_us-gaap_ProfitLoss_01a064cd-b632-7151-be4b-a41d54014082" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodShares_01a064cd-b632-7f32-9908-d5fe246b33e9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchasedDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodShares_01a064cd-b632-7f32-9908-d5fe246b33e9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodValue_01a064cd-b632-7f95-871b-59c88941e64b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchasedDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodValue_01a064cd-b632-7f95-871b-59c88941e64b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockDividendsShares_01a064cd-b632-73de-a821-447279d7a85f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockDividendsShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_us-gaap_StockDividendsShares_01a064cd-b632-73de-a821-447279d7a85f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockDividend_01a064cd-b632-7001-84fe-35b4642e52ea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueStockDividend"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockDividend_01a064cd-b632-7001-84fe-35b4642e52ea" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_01a064cd-b632-7989-a86a-dc1d760ce542" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_01a064cd-b632-7989-a86a-dc1d760ce542" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_01a064cd-b632-71e0-bff6-8b1e04b4f2ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_01a064cd-b632-71e0-bff6-8b1e04b4f2ca" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_01a064cd-b632-7a2b-8e44-c55743ec18e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesIssuedForServices"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesIssuedForServices_01a064cd-b632-7a2b-8e44-c55743ec18e1" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_StockIssuedDuringPeriodValueIssuedForServicesNet_01a064cd-b632-7a26-9801-aea257c95401" xlink:href="innv-20260930.xsd#innv_StockIssuedDuringPeriodValueIssuedForServicesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_innv_StockIssuedDuringPeriodValueIssuedForServicesNet_01a064cd-b632-7a26-9801-aea257c95401" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueIssuedForServices_01a064cd-b632-7365-9148-fd404ec8904f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueIssuedForServices"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueIssuedForServices_01a064cd-b632-7365-9148-fd404ec8904f" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_StockIssuedDuringPeriodSharesConversionOfConvertibleDebentures_01a064cd-b632-7b50-ad75-8a16c8022997" xlink:href="innv-20260930.xsd#innv_StockIssuedDuringPeriodSharesConversionOfConvertibleDebentures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_innv_StockIssuedDuringPeriodSharesConversionOfConvertibleDebentures_01a064cd-b632-7b50-ad75-8a16c8022997" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_StockIssuedDuringPeriodValueConversionOfConvertibleDebentures_01a064cd-b632-76f2-8be4-01a5fadf1649" xlink:href="innv-20260930.xsd#innv_StockIssuedDuringPeriodValueConversionOfConvertibleDebentures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_innv_StockIssuedDuringPeriodValueConversionOfConvertibleDebentures_01a064cd-b632-76f2-8be4-01a5fadf1649" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_01a064cd-b632-7f47-8e41-bf055c9538f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_01a064cd-b632-7f47-8e41-bf055c9538f5" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures_01a064cd-b632-7be7-b7d9-74ec92382981" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures_01a064cd-b632-7be7-b7d9-74ec92382981" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_StockIssuedDuringPeriodSharesEarnoutSharesVested_01a064cd-b632-7372-b753-a610c701e012" xlink:href="innv-20260930.xsd#innv_StockIssuedDuringPeriodSharesEarnoutSharesVested"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_innv_StockIssuedDuringPeriodSharesEarnoutSharesVested_01a064cd-b632-7372-b753-a610c701e012" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_StockIssuedDuringPeriodValueEarnoutSharesVested_01a064cd-b632-7b78-ac8b-2c6e3b69e18c" xlink:href="innv-20260930.xsd#innv_StockIssuedDuringPeriodValueEarnoutSharesVested"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_innv_StockIssuedDuringPeriodValueEarnoutSharesVested_01a064cd-b632-7b78-ac8b-2c6e3b69e18c" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_StockIssuedDuringPeriodSharesEarnoutSharesForfeited_01a1b295-9b08-7162-b51d-609ce630f499" xlink:href="innv-20260930.xsd#innv_StockIssuedDuringPeriodSharesEarnoutSharesForfeited"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_innv_StockIssuedDuringPeriodSharesEarnoutSharesForfeited_01a1b295-9b08-7162-b51d-609ce630f499" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_StockIssuedDuringPeriodValueEarnoutSharesForfeiteures_01a1b295-fb26-7036-b690-dab3a768c02a" xlink:href="innv-20260930.xsd#innv_StockIssuedDuringPeriodValueEarnoutSharesForfeiteures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_innv_StockIssuedDuringPeriodValueEarnoutSharesForfeiteures_01a1b295-fb26-7036-b690-dab3a768c02a" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_OtherComprehensiveIncomeLossExcludingForeignCurrencyTranslationAdjustmentNetOfTax_01a064cd-b632-7d79-8721-b6c94b317233" xlink:href="innv-20260930.xsd#innv_OtherComprehensiveIncomeLossExcludingForeignCurrencyTranslationAdjustmentNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_innv_OtherComprehensiveIncomeLossExcludingForeignCurrencyTranslationAdjustmentNetOfTax_01a064cd-b632-7d79-8721-b6c94b317233" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuanceNetOfTransfers_01a064cd-b632-78db-ab35-8db67648e272" xlink:href="innv-20260930.xsd#innv_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuanceNetOfTransfers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_innv_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuanceNetOfTransfers_01a064cd-b632-78db-ab35-8db67648e272" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Dividends_01a064cd-b632-7499-ae91-42357f0cef78" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Dividends"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_us-gaap_Dividends_01a064cd-b632-7499-ae91-42357f0cef78" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_APICShareBasedPaymentArrangementSharesIncreaseForCostRecognition_01a064cd-b632-713e-a909-5a42e2a5caf6" xlink:href="innv-20260930.xsd#innv_APICShareBasedPaymentArrangementSharesIncreaseForCostRecognition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_innv_APICShareBasedPaymentArrangementSharesIncreaseForCostRecognition_01a064cd-b632-713e-a909-5a42e2a5caf6" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_01a064cd-b632-72b0-b982-6fba680dabc8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_01a064cd-b632-72b0-b982-6fba680dabc8" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings_01a064cd-b632-769e-b625-0cd9eff1d980" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings_01a064cd-b632-769e-b625-0cd9eff1d980" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_AdjustmentsToAdditionalPaidInCapitalPreferredStockDividendsForfeitedUponConversion_01a064cd-b632-72ad-99ab-a4ed1daf83fa" xlink:href="innv-20260930.xsd#innv_AdjustmentsToAdditionalPaidInCapitalPreferredStockDividendsForfeitedUponConversion"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_innv_AdjustmentsToAdditionalPaidInCapitalPreferredStockDividendsForfeitedUponConversion_01a064cd-b632-72ad-99ab-a4ed1daf83fa" xlink:type="arc" order="28"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_AdjustmentsToAdditionalPaidInCapitalReclassificationOfWarrant_01a064cd-b632-73bb-821e-420fff5c5517" xlink:href="innv-20260930.xsd#innv_AdjustmentsToAdditionalPaidInCapitalReclassificationOfWarrant"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_innv_AdjustmentsToAdditionalPaidInCapitalReclassificationOfWarrant_01a064cd-b632-73bb-821e-420fff5c5517" xlink:type="arc" order="29"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_01a064cd-b632-7215-a021-15fb46fe90e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_01a064cd-b632-7215-a021-15fb46fe90e1" xlink:type="arc" order="30"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_01a064cd-b632-7931-930d-6157077aec18" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a064cd-b632-7e75-8fb1-eaa015e80bec" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities_01a064cd-b632-7931-930d-6157077aec18" xlink:type="arc" order="31"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_01a064cd-b632-7f23-8d4c-71066179d7ff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_01a064cd-b632-7f5d-8be6-3a91368a77b2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_01a064cd-b632-7164-b80e-73714180448f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_01a064cd-b632-7b83-bf29-61de18e1d374" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInTemporaryEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-78c5-9b8d-8607425cba43" xlink:to="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_01a064cd-b632-7b83-bf29-61de18e1d374" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquitySharesOutstanding_01a064cd-b632-78c1-b4e6-4c082a85a75a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquitySharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_01a064cd-b632-7b83-bf29-61de18e1d374" xlink:to="loc_us-gaap_TemporaryEquitySharesOutstanding_01a064cd-b632-78c1-b4e6-4c082a85a75a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_01a064cd-b632-7f56-8971-ccd83f2322d1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityCarryingAmountAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_01a064cd-b632-7b83-bf29-61de18e1d374" xlink:to="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_01a064cd-b632-7f56-8971-ccd83f2322d1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TemporaryEquityStockIssuedDuringPeriodSharesConversionOfDebt_01a064cd-b632-7046-976f-cf6da2bcda67" xlink:href="innv-20260930.xsd#innv_TemporaryEquityStockIssuedDuringPeriodSharesConversionOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_01a064cd-b632-7b83-bf29-61de18e1d374" xlink:to="loc_innv_TemporaryEquityStockIssuedDuringPeriodSharesConversionOfDebt_01a064cd-b632-7046-976f-cf6da2bcda67" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TemporaryEquityStockIssuedDuringPeriodValueConversionOfDebt_01a064cd-b632-7632-933e-a2a08b4b87bf" xlink:href="innv-20260930.xsd#innv_TemporaryEquityStockIssuedDuringPeriodValueConversionOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_01a064cd-b632-7b83-bf29-61de18e1d374" xlink:to="loc_innv_TemporaryEquityStockIssuedDuringPeriodValueConversionOfDebt_01a064cd-b632-7632-933e-a2a08b4b87bf" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues_01a064cd-b632-7a18-8efc-eae164076992" xlink:href="innv-20260930.xsd#innv_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_01a064cd-b632-7b83-bf29-61de18e1d374" xlink:to="loc_innv_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues_01a064cd-b632-7a18-8efc-eae164076992" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues_01a064cd-b632-7e2d-91c6-73b4cee41904" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_01a064cd-b632-7b83-bf29-61de18e1d374" xlink:to="loc_us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues_01a064cd-b632-7e2d-91c6-73b4cee41904" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TemporaryEquityStockIssuedDuringPeriodSharesIssuedForServices_01a064cd-b632-7398-8591-0fcfab0fc6db" xlink:href="innv-20260930.xsd#innv_TemporaryEquityStockIssuedDuringPeriodSharesIssuedForServices"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_01a064cd-b632-7b83-bf29-61de18e1d374" xlink:to="loc_innv_TemporaryEquityStockIssuedDuringPeriodSharesIssuedForServices_01a064cd-b632-7398-8591-0fcfab0fc6db" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TemporaryEquityStockIssuedDuringPeriodValueIssuedForServices_01a064cd-b632-70f2-868b-d1042410f256" xlink:href="innv-20260930.xsd#innv_TemporaryEquityStockIssuedDuringPeriodValueIssuedForServices"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_01a064cd-b632-7b83-bf29-61de18e1d374" xlink:to="loc_innv_TemporaryEquityStockIssuedDuringPeriodValueIssuedForServices_01a064cd-b632-70f2-868b-d1042410f256" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityAccretionOfDividends_01a064cd-b632-7b40-a270-7102bec0e984" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityAccretionOfDividends"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_01a064cd-b632-7b83-bf29-61de18e1d374" xlink:to="loc_us-gaap_TemporaryEquityAccretionOfDividends_01a064cd-b632-7b40-a270-7102bec0e984" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TemporaryEquitySharesConversionOfConvertibleSecurities_01a064cd-b632-731a-a969-fa04fb081ab8" xlink:href="innv-20260930.xsd#innv_TemporaryEquitySharesConversionOfConvertibleSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_01a064cd-b632-7b83-bf29-61de18e1d374" xlink:to="loc_innv_TemporaryEquitySharesConversionOfConvertibleSecurities_01a064cd-b632-731a-a969-fa04fb081ab8" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TemporaryEquityValueConversionOfConvertibleSecurities_01a064cd-b632-7323-b37b-3f1e20019195" xlink:href="innv-20260930.xsd#innv_TemporaryEquityValueConversionOfConvertibleSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_01a064cd-b632-7b83-bf29-61de18e1d374" xlink:to="loc_innv_TemporaryEquityValueConversionOfConvertibleSecurities_01a064cd-b632-7323-b37b-3f1e20019195" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquitySharesOutstanding_01a064cd-b632-7698-a555-68a9047df52d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquitySharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_01a064cd-b632-7c23-9eb1-049e0d58ec52" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityCarryingAmountAttributableToParent"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/ConsolidatedStatementsofCashFlows" xlink:type="simple" xlink:href="innv-20260930.xsd#ConsolidatedStatementsofCashFlows"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/ConsolidatedStatementsofCashFlows" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_01a064cd-b632-7089-b0dd-cf5e2b520be8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_01a064cd-b632-7eb6-8023-a8db1714848e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-7089-b0dd-cf5e2b520be8" xlink:to="loc_us-gaap_StatementTable_01a064cd-b632-7eb6-8023-a8db1714848e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a064cd-b632-78a0-a3c1-872d7375e767" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_01a064cd-b632-7eb6-8023-a8db1714848e" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a064cd-b632-78a0-a3c1-872d7375e767" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a064cd-b632-78a0-a3c1-872d7375e767_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a064cd-b632-78a0-a3c1-872d7375e767" xlink:to="loc_us-gaap_RelatedPartyDomain_01a064cd-b632-78a0-a3c1-872d7375e767_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a064cd-b632-796c-9f1c-1cc4cf6b28bf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a064cd-b632-78a0-a3c1-872d7375e767" xlink:to="loc_us-gaap_RelatedPartyDomain_01a064cd-b632-796c-9f1c-1cc4cf6b28bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonrelatedPartyMember_01a064cd-b632-75f0-8e79-e27e9cba0bef" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonrelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_01a064cd-b632-796c-9f1c-1cc4cf6b28bf" xlink:to="loc_us-gaap_NonrelatedPartyMember_01a064cd-b632-75f0-8e79-e27e9cba0bef" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_01a064cd-b632-7e8f-8fbf-c11bc1caa478" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_01a064cd-b632-796c-9f1c-1cc4cf6b28bf" xlink:to="loc_us-gaap_RelatedPartyMember_01a064cd-b632-7e8f-8fbf-c11bc1caa478" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-7e1a-9405-ddf9f4cbc6f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-7089-b0dd-cf5e2b520be8" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-7e1a-9405-ddf9f4cbc6f5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_01a064cd-b632-7944-81b7-0dd10d58d620" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-7e1a-9405-ddf9f4cbc6f5" xlink:to="loc_us-gaap_ProfitLoss_01a064cd-b632-7944-81b7-0dd10d58d620" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-78ec-b77c-9074943147ea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-7e1a-9405-ddf9f4cbc6f5" xlink:to="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-78ec-b77c-9074943147ea" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensation_01a064cd-b632-740f-bc67-6b9c6c04ae4b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-78ec-b77c-9074943147ea" xlink:to="loc_us-gaap_ShareBasedCompensation_01a064cd-b632-740f-bc67-6b9c6c04ae4b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_NoncashInterestIncome_01a064cd-b632-7f13-9e87-c22b8a5bfa0d" xlink:href="innv-20260930.xsd#innv_NoncashInterestIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-78ec-b77c-9074943147ea" xlink:to="loc_innv_NoncashInterestIncome_01a064cd-b632-7f13-9e87-c22b8a5bfa0d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_UnrealizedGainLossOnFinancialLiabilities_01a064cd-b632-77da-a38a-322d45899578" xlink:href="innv-20260930.xsd#innv_UnrealizedGainLossOnFinancialLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-78ec-b77c-9074943147ea" xlink:to="loc_innv_UnrealizedGainLossOnFinancialLiabilities_01a064cd-b632-77da-a38a-322d45899578" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfDebtDiscountPremium_01a064cd-b632-7589-87fa-60c1ecbf4dac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AmortizationOfDebtDiscountPremium"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-78ec-b77c-9074943147ea" xlink:to="loc_us-gaap_AmortizationOfDebtDiscountPremium_01a064cd-b632-7589-87fa-60c1ecbf4dac" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_GainLossOnInvestmentsIncludingRoundingAdjustment_01a064cd-b632-7ca9-94bd-2393ec3da76d" xlink:href="innv-20260930.xsd#innv_GainLossOnInvestmentsIncludingRoundingAdjustment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-78ec-b77c-9074943147ea" xlink:to="loc_innv_GainLossOnInvestmentsIncludingRoundingAdjustment_01a064cd-b632-7ca9-94bd-2393ec3da76d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaidInKindInterest_01a064cd-b632-765a-b386-be41c1bf8012" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaidInKindInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-78ec-b77c-9074943147ea" xlink:to="loc_us-gaap_PaidInKindInterest_01a064cd-b632-765a-b386-be41c1bf8012" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_IncomeLossFromEquityMethodInvestmentsWithRoundingAdjustment_01a064cd-b632-7dbb-b128-a93fb1e5832c" xlink:href="innv-20260930.xsd#innv_IncomeLossFromEquityMethodInvestmentsWithRoundingAdjustment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-78ec-b77c-9074943147ea" xlink:to="loc_innv_IncomeLossFromEquityMethodInvestmentsWithRoundingAdjustment_01a064cd-b632-7dbb-b128-a93fb1e5832c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleRealizedGain_01a064cd-b632-7ab6-ad31-e9e3a40836f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleRealizedGain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-78ec-b77c-9074943147ea" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleRealizedGain_01a064cd-b632-7ab6-ad31-e9e3a40836f8" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_01a064cd-b632-76e7-8cb7-90792e344ad7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-78ec-b77c-9074943147ea" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_01a064cd-b632-76e7-8cb7-90792e344ad7" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_01a064cd-b632-7869-8c1f-c80a3418aca6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-78ec-b77c-9074943147ea" xlink:to="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_01a064cd-b632-7869-8c1f-c80a3418aca6" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_01a064cd-b632-7ad2-aa0f-6a48249866d0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSaleOfPropertyPlantEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-78ec-b77c-9074943147ea" xlink:to="loc_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_01a064cd-b632-7ad2-aa0f-6a48249866d0" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationAmortizationAndAccretionNet_01a064cd-b632-7d1c-9d3a-fee550de37dd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepreciationAmortizationAndAccretionNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-78ec-b77c-9074943147ea" xlink:to="loc_us-gaap_DepreciationAmortizationAndAccretionNet_01a064cd-b632-7d1c-9d3a-fee550de37dd" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_01a064cd-b632-704d-a1a9-41c4b401112e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-78ec-b77c-9074943147ea" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_01a064cd-b632-704d-a1a9-41c4b401112e" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncashIncomeExpense_01a064cd-b632-7081-b319-31ce14019494" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNoncashIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-78ec-b77c-9074943147ea" xlink:to="loc_us-gaap_OtherNoncashIncomeExpense_01a064cd-b632-7081-b319-31ce14019494" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_01a064cd-b632-76f6-8ec0-b15ba4f62728" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-78ec-b77c-9074943147ea" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_01a064cd-b632-76f6-8ec0-b15ba4f62728" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_01a064cd-b632-7a39-970d-bf3f6a8cc833" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_01a064cd-b632-76f6-8ec0-b15ba4f62728" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_01a064cd-b632-7a39-970d-bf3f6a8cc833" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_01a064cd-b632-75f4-963a-e0f9015dbf8d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_01a064cd-b632-76f6-8ec0-b15ba4f62728" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_01a064cd-b632-75f4-963a-e0f9015dbf8d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_01a064cd-b632-7892-b3a6-82dda6054c41" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInInventories"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_01a064cd-b632-76f6-8ec0-b15ba4f62728" xlink:to="loc_us-gaap_IncreaseDecreaseInInventories_01a064cd-b632-7892-b3a6-82dda6054c41" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_01a064cd-b632-7cb3-93ab-99ba99a4f3a2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccountsPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_01a064cd-b632-76f6-8ec0-b15ba4f62728" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayable_01a064cd-b632-7cb3-93ab-99ba99a4f3a2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_01a064cd-b632-7c94-b7fa-13b21117cf8c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_01a064cd-b632-76f6-8ec0-b15ba4f62728" xlink:to="loc_us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_01a064cd-b632-7c94-b7fa-13b21117cf8c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherAccruedLiabilities_01a064cd-b632-72cf-a126-ce1892b97528" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInOtherAccruedLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_01a064cd-b632-76f6-8ec0-b15ba4f62728" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherAccruedLiabilities_01a064cd-b632-72cf-a126-ce1892b97528" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredCompensation_01a064cd-b632-791f-aad1-d3b88952a370" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInDeferredCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_01a064cd-b632-76f6-8ec0-b15ba4f62728" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredCompensation_01a064cd-b632-791f-aad1-d3b88952a370" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable_01a064cd-b632-7ee8-a406-c99bfe0fdf78" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_01a064cd-b632-76f6-8ec0-b15ba4f62728" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable_01a064cd-b632-7ee8-a406-c99bfe0fdf78" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_IncreaseDecreaseInPreferredStockIssuanceLiability_01a08ba3-a123-7363-968c-51947a079ef2" xlink:href="innv-20260930.xsd#innv_IncreaseDecreaseInPreferredStockIssuanceLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_01a064cd-b632-76f6-8ec0-b15ba4f62728" xlink:to="loc_innv_IncreaseDecreaseInPreferredStockIssuanceLiability_01a08ba3-a123-7363-968c-51947a079ef2" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_01a064cd-b632-737e-b0c2-e207b48c5a76" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInOtherOperatingLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_01a064cd-b632-76f6-8ec0-b15ba4f62728" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherOperatingLiabilities_01a064cd-b632-737e-b0c2-e207b48c5a76" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherNoncurrentAssets_01a08ba3-a123-723d-862f-d2f3a0bc32cf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInOtherNoncurrentAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_01a064cd-b632-76f6-8ec0-b15ba4f62728" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherNoncurrentAssets_01a08ba3-a123-723d-862f-d2f3a0bc32cf" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_PaymentOfPatentInstallment_01a064cd-b632-70ef-981e-67a5e69d5806" xlink:href="innv-20260930.xsd#innv_PaymentOfPatentInstallment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_01a064cd-b632-76f6-8ec0-b15ba4f62728" xlink:to="loc_innv_PaymentOfPatentInstallment_01a064cd-b632-70ef-981e-67a5e69d5806" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInContractWithCustomerLiability_01a064cd-b632-7ab5-95c0-b9192f812518" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInContractWithCustomerLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_01a064cd-b632-76f6-8ec0-b15ba4f62728" xlink:to="loc_us-gaap_IncreaseDecreaseInContractWithCustomerLiability_01a064cd-b632-7ab5-95c0-b9192f812518" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_01a064cd-b632-7b71-b0ac-9131d4120f9d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_01a064cd-b632-7e1a-9405-ddf9f4cbc6f5" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_01a064cd-b632-7b71-b0ac-9131d4120f9d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_01a064cd-b632-72fe-92b5-d31f8edc2602" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-7089-b0dd-cf5e2b520be8" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_01a064cd-b632-72fe-92b5-d31f8edc2602" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_01a064cd-b632-7f00-8f3d-0d02d1ac1bf7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_01a064cd-b632-72fe-92b5-d31f8edc2602" xlink:to="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_01a064cd-b632-7f00-8f3d-0d02d1ac1bf7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_01a064cd-b632-76b4-9b74-c05ba6bf4928" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_01a064cd-b632-72fe-92b5-d31f8edc2602" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_01a064cd-b632-76b4-9b74-c05ba6bf4928" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_01a064cd-b632-7583-84a5-fec4a0fda2b0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_01a064cd-b632-72fe-92b5-d31f8edc2602" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_01a064cd-b632-7583-84a5-fec4a0fda2b0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_01a064cd-b632-7a67-9f74-61549848f274" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-7089-b0dd-cf5e2b520be8" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_01a064cd-b632-7a67-9f74-61549848f274" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOrSaleOfEquity_01a064cd-b632-797c-a6b6-38ffdcb1f20e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOrSaleOfEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_01a064cd-b632-7a67-9f74-61549848f274" xlink:to="loc_us-gaap_ProceedsFromIssuanceOrSaleOfEquity_01a064cd-b632-797c-a6b6-38ffdcb1f20e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromMinorityShareholders_01a064cd-b632-747b-86f9-f25807e2d4e9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromMinorityShareholders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_01a064cd-b632-7a67-9f74-61549848f274" xlink:to="loc_us-gaap_ProceedsFromMinorityShareholders_01a064cd-b632-747b-86f9-f25807e2d4e9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromConvertibleDebt_01a064cd-b632-775f-84ab-baaf35b9b7d3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromConvertibleDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_01a064cd-b632-7a67-9f74-61549848f274" xlink:to="loc_us-gaap_ProceedsFromConvertibleDebt_01a064cd-b632-775f-84ab-baaf35b9b7d3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfOtherLongTermDebt_01a064cd-b632-7561-b113-3a3889d0c458" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfOtherLongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_01a064cd-b632-7a67-9f74-61549848f274" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfOtherLongTermDebt_01a064cd-b632-7561-b113-3a3889d0c458" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfDebt_01a064cd-b632-7675-ab30-16f241ebc07c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RepaymentsOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_01a064cd-b632-7a67-9f74-61549848f274" xlink:to="loc_us-gaap_RepaymentsOfDebt_01a064cd-b632-7675-ab30-16f241ebc07c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_01a1a86d-ca49-7c7b-b8b0-b7960c560e5a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_01a064cd-b632-7a67-9f74-61549848f274" xlink:to="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_01a1a86d-ca49-7c7b-b8b0-b7960c560e5a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_PaymentOfDividendsAndOtherFinancingActivities_01a064cd-b632-7695-85ac-071684b0f5ba" xlink:href="innv-20260930.xsd#innv_PaymentOfDividendsAndOtherFinancingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_01a064cd-b632-7a67-9f74-61549848f274" xlink:to="loc_innv_PaymentOfDividendsAndOtherFinancingActivities_01a064cd-b632-7695-85ac-071684b0f5ba" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_01a064cd-b632-7cec-a6ab-3ac6262ba8bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_01a064cd-b632-7a67-9f74-61549848f274" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_01a064cd-b632-7cec-a6ab-3ac6262ba8bc" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_01a064cd-b632-7a32-a62f-9a00793fd412" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-7089-b0dd-cf5e2b520be8" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_01a064cd-b632-7a32-a62f-9a00793fd412" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_01a064cd-b632-7c18-9988-5abe936fad39" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-7089-b0dd-cf5e2b520be8" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_01a064cd-b632-7c18-9988-5abe936fad39" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_01a064cd-b632-79fd-8711-14d43c8fd4ab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalCashFlowInformationAbstract_01a064cd-b632-75d2-a0ff-6357a9d94081" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SupplementalCashFlowInformationAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-7089-b0dd-cf5e2b520be8" xlink:to="loc_us-gaap_SupplementalCashFlowInformationAbstract_01a064cd-b632-75d2-a0ff-6357a9d94081" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPaidNet_01a064cd-b632-7d34-9875-16a8702dc25f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestPaidNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract_01a064cd-b632-75d2-a0ff-6357a9d94081" xlink:to="loc_us-gaap_InterestPaidNet_01a064cd-b632-7d34-9875-16a8702dc25f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_01a064cd-b632-7e88-91dd-f9f5b5fe41b7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a064cd-b632-7089-b0dd-cf5e2b520be8" xlink:to="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_01a064cd-b632-7e88-91dd-f9f5b5fe41b7" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_01a1a86e-e834-7f5a-88d1-ff6705ef165a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalExpendituresIncurredButNotYetPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_01a064cd-b632-7e88-91dd-f9f5b5fe41b7" xlink:to="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_01a1a86e-e834-7f5a-88d1-ff6705ef165a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferToInvestments_01a064cd-b632-70fb-abaf-463cbf6ffef2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransferToInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_01a064cd-b632-7e88-91dd-f9f5b5fe41b7" xlink:to="loc_us-gaap_TransferToInvestments_01a064cd-b632-70fb-abaf-463cbf6ffef2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedGainLoss_01a08ba4-d0d2-710a-9124-845e096fb3f1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_01a064cd-b632-7e88-91dd-f9f5b5fe41b7" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedGainLoss_01a08ba4-d0d2-710a-9124-845e096fb3f1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_RecognitionOfRightOfUseAssetAndLeaseLiability_01a08ba4-d0d2-7beb-9498-d41d9a782871" xlink:href="innv-20260930.xsd#innv_RecognitionOfRightOfUseAssetAndLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_01a064cd-b632-7e88-91dd-f9f5b5fe41b7" xlink:to="loc_innv_RecognitionOfRightOfUseAssetAndLeaseLiability_01a08ba4-d0d2-7beb-9498-d41d9a782871" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_IssuanceOfTemporaryEquityForExtinguishmentOfDebt_01a064cd-b632-7d61-905a-e3cd695da52f" xlink:href="innv-20260930.xsd#innv_IssuanceOfTemporaryEquityForExtinguishmentOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_01a064cd-b632-7e88-91dd-f9f5b5fe41b7" xlink:to="loc_innv_IssuanceOfTemporaryEquityForExtinguishmentOfDebt_01a064cd-b632-7d61-905a-e3cd695da52f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssued1_01a064cd-b632-7121-846b-41c48c6706e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssued1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_01a064cd-b632-7e88-91dd-f9f5b5fe41b7" xlink:to="loc_us-gaap_StockIssued1_01a064cd-b632-7121-846b-41c48c6706e3" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ConversionOfDebtSecuritiesAvailableForSaleToEquityMethodInvestments_01a064cd-b632-7fae-9a12-c5c0a49528b3" xlink:href="innv-20260930.xsd#innv_ConversionOfDebtSecuritiesAvailableForSaleToEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_01a064cd-b632-7e88-91dd-f9f5b5fe41b7" xlink:to="loc_innv_ConversionOfDebtSecuritiesAvailableForSaleToEquityMethodInvestments_01a064cd-b632-7fae-9a12-c5c0a49528b3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionConvertedInstrumentAmount1_01a064cd-b632-75e2-9eb5-418531c9f7a0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtConversionConvertedInstrumentAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_01a064cd-b632-7e88-91dd-f9f5b5fe41b7" xlink:to="loc_us-gaap_DebtConversionConvertedInstrumentAmount1_01a064cd-b632-75e2-9eb5-418531c9f7a0" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_IssuanceOfVestedRestrictedStockUnits_01a064cd-b632-7596-9e53-39df76f873e2" xlink:href="innv-20260930.xsd#innv_IssuanceOfVestedRestrictedStockUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_01a064cd-b632-7e88-91dd-f9f5b5fe41b7" xlink:to="loc_innv_IssuanceOfVestedRestrictedStockUnits_01a064cd-b632-7596-9e53-39df76f873e2" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims_01a064cd-b632-7184-89f0-9d9bf284d564" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_01a064cd-b632-7e88-91dd-f9f5b5fe41b7" xlink:to="loc_us-gaap_IssuanceOfStockAndWarrantsForServicesOrClaims_01a064cd-b632-7184-89f0-9d9bf284d564" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConversionOfStockAmountConverted1_01a064cd-b632-7d06-93e1-586420f7494c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConversionOfStockAmountConverted1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_01a064cd-b632-7e88-91dd-f9f5b5fe41b7" xlink:to="loc_us-gaap_ConversionOfStockAmountConverted1_01a064cd-b632-7d06-93e1-586420f7494c" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TemporaryEquityConvertedToPermanentEquity_01a064cd-b632-7836-ada0-6f8148017a13" xlink:href="innv-20260930.xsd#innv_TemporaryEquityConvertedToPermanentEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_01a064cd-b632-7e88-91dd-f9f5b5fe41b7" xlink:to="loc_innv_TemporaryEquityConvertedToPermanentEquity_01a064cd-b632-7836-ada0-6f8148017a13" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_EmbeddedDerivativeLiabilityIncludedInDebt_01a064cd-b632-7fda-9264-94e5a37c6740" xlink:href="innv-20260930.xsd#innv_EmbeddedDerivativeLiabilityIncludedInDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_01a064cd-b632-7e88-91dd-f9f5b5fe41b7" xlink:to="loc_innv_EmbeddedDerivativeLiabilityIncludedInDebt_01a064cd-b632-7fda-9264-94e5a37c6740" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_NoncashEquityReallocation_01a064cd-b632-751c-ae5e-52e41f760251" xlink:href="innv-20260930.xsd#innv_NoncashEquityReallocation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_01a064cd-b632-7e88-91dd-f9f5b5fe41b7" xlink:to="loc_innv_NoncashEquityReallocation_01a064cd-b632-751c-ae5e-52e41f760251" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_DerecognitionOfEmbeddedDerivativeLiability_01a08ba4-d0d2-7b78-8f03-b129cefccc2e" xlink:href="innv-20260930.xsd#innv_DerecognitionOfEmbeddedDerivativeLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_01a064cd-b632-7e88-91dd-f9f5b5fe41b7" xlink:to="loc_innv_DerecognitionOfEmbeddedDerivativeLiability_01a08ba4-d0d2-7b78-8f03-b129cefccc2e" xlink:type="arc" order="15"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/InvestmentsNarrativeDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#InvestmentsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/InvestmentsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_01a064cd-b632-7935-bedd-416fb5989baf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_01a064cd-b632-72c6-b1db-7b711f3499ab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_01a064cd-b632-7935-bedd-416fb5989baf" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_01a064cd-b632-72c6-b1db-7b711f3499ab" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_01a064cd-b632-7a84-923e-91b05f7a43c7" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_01a064cd-b632-72c6-b1db-7b711f3499ab" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_01a064cd-b632-7a84-923e-91b05f7a43c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_01a064cd-b632-7a84-923e-91b05f7a43c7_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_01a064cd-b632-7a84-923e-91b05f7a43c7" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_01a064cd-b632-7a84-923e-91b05f7a43c7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_01a064cd-b632-75d3-8cd0-59cb7acb0e0f" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_01a064cd-b632-7a84-923e-91b05f7a43c7" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_01a064cd-b632-75d3-8cd0-59cb7acb0e0f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_AeroFlexxLLCMember_01a064cd-b632-7a70-b4a9-ff5bf787adac" xlink:href="innv-20260930.xsd#innv_AeroFlexxLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_01a064cd-b632-75d3-8cd0-59cb7acb0e0f" xlink:to="loc_innv_AeroFlexxLLCMember_01a064cd-b632-7a70-b4a9-ff5bf787adac" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_01a064cd-b632-7388-8533-4fed1ee2ffb1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_01a064cd-b632-7935-bedd-416fb5989baf" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_01a064cd-b632-7388-8533-4fed1ee2ffb1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_DebtSecuritiesAvailableForSaleMaximumCapacity_01a064cd-b632-775c-97f4-4ec1c6890267" xlink:href="innv-20260930.xsd#innv_DebtSecuritiesAvailableForSaleMaximumCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_01a064cd-b632-7935-bedd-416fb5989baf" xlink:to="loc_innv_DebtSecuritiesAvailableForSaleMaximumCapacity_01a064cd-b632-775c-97f4-4ec1c6890267" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_DebtSecuritiesAvailableForSaleConvertibleConversionPricePercentage_01a064cd-b632-765e-8996-12ce518288eb" xlink:href="innv-20260930.xsd#innv_DebtSecuritiesAvailableForSaleConvertibleConversionPricePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_01a064cd-b632-7935-bedd-416fb5989baf" xlink:to="loc_innv_DebtSecuritiesAvailableForSaleConvertibleConversionPricePercentage_01a064cd-b632-765e-8996-12ce518288eb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ConversionOfDebtSecuritiesAvailableForSaleToEquityMethodInvestments_01a064cd-b632-7117-9e7a-ecc525c8b7d1" xlink:href="innv-20260930.xsd#innv_ConversionOfDebtSecuritiesAvailableForSaleToEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_01a064cd-b632-7935-bedd-416fb5989baf" xlink:to="loc_innv_ConversionOfDebtSecuritiesAvailableForSaleToEquityMethodInvestments_01a064cd-b632-7117-9e7a-ecc525c8b7d1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TransferToInvestmentsPrice_01a064cd-b632-70e2-bda1-659ba26ed518" xlink:href="innv-20260930.xsd#innv_TransferToInvestmentsPrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_01a064cd-b632-7935-bedd-416fb5989baf" xlink:to="loc_innv_TransferToInvestmentsPrice_01a064cd-b632-70e2-bda1-659ba26ed518" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleRealizedGain_01a064cd-b632-71ad-987f-a1cf3cfc5a15" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleRealizedGain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_01a064cd-b632-7935-bedd-416fb5989baf" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleRealizedGain_01a064cd-b632-71ad-987f-a1cf3cfc5a15" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_DebtSecuritiesAvailableForSaleGrossDrawn_01a064cd-b632-7a8a-8d07-a4e1c8f6339d" xlink:href="innv-20260930.xsd#innv_DebtSecuritiesAvailableForSaleGrossDrawn"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_01a064cd-b632-7935-bedd-416fb5989baf" xlink:to="loc_innv_DebtSecuritiesAvailableForSaleGrossDrawn_01a064cd-b632-7a8a-8d07-a4e1c8f6339d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferToInvestments_01a064cd-b632-7cf7-a215-87abb1d893f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TransferToInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_01a064cd-b632-7935-bedd-416fb5989baf" xlink:to="loc_us-gaap_TransferToInvestments_01a064cd-b632-7cf7-a215-87abb1d893f3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_01a064cd-b632-72a5-87d6-347b8142555b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_01a064cd-b632-7935-bedd-416fb5989baf" xlink:to="loc_us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_01a064cd-b632-72a5-87d6-347b8142555b" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_01a064cd-b632-7217-9583-32adc625c2e2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_01a064cd-b632-7935-bedd-416fb5989baf" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_01a064cd-b632-7217-9583-32adc625c2e2" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherReceivablesNetCurrent_01a064cd-b632-7d0d-8f1e-93f7f458909c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherReceivablesNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_01a064cd-b632-7935-bedd-416fb5989baf" xlink:to="loc_us-gaap_OtherReceivablesNetCurrent_01a064cd-b632-7d0d-8f1e-93f7f458909c" xlink:type="arc" order="10"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/FairValueFairValueHierarchyforAssetsandLiabilitiesMeasuredatFairValueDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#FairValueFairValueHierarchyforAssetsandLiabilitiesMeasuredatFairValueDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/FairValueFairValueHierarchyforAssetsandLiabilitiesMeasuredatFairValueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_01a064cd-b632-7018-b783-42cc684902ef" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_01a064cd-b632-733a-911c-b0ca91580d68" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_01a064cd-b632-7018-b783-42cc684902ef" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_01a064cd-b632-733a-911c-b0ca91580d68" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_01a064cd-b632-7e15-bd8b-51e983b9c064" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_01a064cd-b632-733a-911c-b0ca91580d68" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_01a064cd-b632-7e15-bd8b-51e983b9c064" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a064cd-b632-7e15-bd8b-51e983b9c064_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_01a064cd-b632-7e15-bd8b-51e983b9c064" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a064cd-b632-7e15-bd8b-51e983b9c064_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a064cd-b632-755e-9903-6b21eaf0c6c2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_01a064cd-b632-7e15-bd8b-51e983b9c064" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a064cd-b632-755e-9903-6b21eaf0c6c2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_01a064cd-b632-79e5-8077-6404f5e39df6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a064cd-b632-755e-9903-6b21eaf0c6c2" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_01a064cd-b632-79e5-8077-6404f5e39df6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_01a064cd-b632-7216-89d3-6daa043571b8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a064cd-b632-755e-9903-6b21eaf0c6c2" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_01a064cd-b632-7216-89d3-6daa043571b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_01a064cd-b632-7154-80c1-4070ed779a2a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a064cd-b632-755e-9903-6b21eaf0c6c2" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_01a064cd-b632-7154-80c1-4070ed779a2a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b632-7ba6-877a-834567480fcd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_01a064cd-b632-733a-911c-b0ca91580d68" xlink:to="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b632-7ba6-877a-834567480fcd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-7ba6-877a-834567480fcd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b632-7ba6-877a-834567480fcd" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-7ba6-877a-834567480fcd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-761b-a29d-e4e600bb2b7c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b632-7ba6-877a-834567480fcd" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-761b-a29d-e4e600bb2b7c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_A2024WTIWarrantMember_01a064cd-b632-7caf-b1dd-5ab34ae371a8" xlink:href="innv-20260930.xsd#innv_A2024WTIWarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-761b-a29d-e4e600bb2b7c" xlink:to="loc_innv_A2024WTIWarrantMember_01a064cd-b632-7caf-b1dd-5ab34ae371a8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_A2025WTIWarrantMember_01a064cd-b632-7c32-b02b-19af21e824bd" xlink:href="innv-20260930.xsd#innv_A2025WTIWarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-761b-a29d-e4e600bb2b7c" xlink:to="loc_innv_A2025WTIWarrantMember_01a064cd-b632-7c32-b02b-19af21e824bd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_PrivatePlacementWarrantsMember_01a064cd-b632-7867-98c1-7365f1e10ab1" xlink:href="innv-20260930.xsd#innv_PrivatePlacementWarrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-761b-a29d-e4e600bb2b7c" xlink:to="loc_innv_PrivatePlacementWarrantsMember_01a064cd-b632-7867-98c1-7365f1e10ab1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosureAbstract_01a064cd-b632-72d8-9f60-f12e1b511a65" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_01a064cd-b632-7018-b783-42cc684902ef" xlink:to="loc_us-gaap_AssetsFairValueDisclosureAbstract_01a064cd-b632-72d8-9f60-f12e1b511a65" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFVNINoncurrent_01a064cd-b632-70b9-ae90-750a000b1f16" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesFVNINoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_01a064cd-b632-72d8-9f60-f12e1b511a65" xlink:to="loc_us-gaap_EquitySecuritiesFVNINoncurrent_01a064cd-b632-70b9-ae90-750a000b1f16" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_01a064cd-b632-7b1a-9bef-59de264c18f6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_01a064cd-b632-72d8-9f60-f12e1b511a65" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_01a064cd-b632-7b1a-9bef-59de264c18f6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_01a064cd-b632-7e41-8401-47f7cd12cd73" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_01a064cd-b632-7018-b783-42cc684902ef" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_01a064cd-b632-7e41-8401-47f7cd12cd73" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_DerivativeInstrumentContingentConsiderationLiability_01a064cd-b632-77d8-9373-5283fdc4c3e7" xlink:href="innv-20260930.xsd#innv_DerivativeInstrumentContingentConsiderationLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_01a064cd-b632-7e41-8401-47f7cd12cd73" xlink:to="loc_innv_DerivativeInstrumentContingentConsiderationLiability_01a064cd-b632-77d8-9373-5283fdc4c3e7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantsAndRightsOutstanding_01a064cd-b632-7059-8b6c-f4d89172b2d0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WarrantsAndRightsOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_01a064cd-b632-7e41-8401-47f7cd12cd73" xlink:to="loc_us-gaap_WarrantsAndRightsOutstanding_01a064cd-b632-7059-8b6c-f4d89172b2d0" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/FairValueChangesinFairValueofLevel3AssetsDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#FairValueChangesinFairValueofLevel3AssetsDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/FairValueChangesinFairValueofLevel3AssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_01a064cd-b632-7291-9848-b8913866e6f9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_01a064cd-b632-7e40-94a8-05447a40fe2b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_01a064cd-b632-7291-9848-b8913866e6f9" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_01a064cd-b632-7e40-94a8-05447a40fe2b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByAssetClassAxis_01a064cd-b632-734e-aaa9-85ccc1a42982" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByAssetClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_01a064cd-b632-7e40-94a8-05447a40fe2b" xlink:to="loc_us-gaap_FairValueByAssetClassAxis_01a064cd-b632-734e-aaa9-85ccc1a42982" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_01a064cd-b632-734e-aaa9-85ccc1a42982_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_01a064cd-b632-734e-aaa9-85ccc1a42982" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_01a064cd-b632-734e-aaa9-85ccc1a42982_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_01a064cd-b632-7313-af5f-93a502b609e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_01a064cd-b632-734e-aaa9-85ccc1a42982" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_01a064cd-b632-7313-af5f-93a502b609e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesMember_01a064cd-b632-7202-9fd0-4d8de3d241d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_01a064cd-b632-7313-af5f-93a502b609e4" xlink:to="loc_us-gaap_DebtSecuritiesMember_01a064cd-b632-7202-9fd0-4d8de3d241d8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_01a064cd-b632-76f7-b676-96b8911ebf9b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_01a064cd-b632-7291-9848-b8913866e6f9" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_01a064cd-b632-76f7-b676-96b8911ebf9b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_01a064cd-b632-7e3e-ad3c-170f29e65c93" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_01a064cd-b632-76f7-b676-96b8911ebf9b" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_01a064cd-b632-7e3e-ad3c-170f29e65c93" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetIssues_01a064cd-b632-7366-abba-419353047fa9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_01a064cd-b632-76f7-b676-96b8911ebf9b" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetIssues_01a064cd-b632-7366-abba-419353047fa9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements_01a064cd-b632-7174-b35b-891ed134efb1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_01a064cd-b632-76f7-b676-96b8911ebf9b" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements_01a064cd-b632-7174-b35b-891ed134efb1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1_01a064cd-b632-78bd-9ce3-b8ae4b284211" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_01a064cd-b632-76f7-b676-96b8911ebf9b" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1_01a064cd-b632-78bd-9ce3-b8ae4b284211" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_01a064cd-b632-75f2-9840-793821157900" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/FairValueChangesinFairValueofLevel3LiabilitiesDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#FairValueChangesinFairValueofLevel3LiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/FairValueChangesinFairValueofLevel3LiabilitiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_01a064cd-b632-7c5a-9549-faab1895288e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_01a064cd-b632-72e9-b4e5-a3ccfde50442" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_01a064cd-b632-7c5a-9549-faab1895288e" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_01a064cd-b632-72e9-b4e5-a3ccfde50442" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByLiabilityClassAxis_01a064cd-b632-7958-bdd4-522bd0fbbb6a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByLiabilityClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_01a064cd-b632-72e9-b4e5-a3ccfde50442" xlink:to="loc_us-gaap_FairValueByLiabilityClassAxis_01a064cd-b632-7958-bdd4-522bd0fbbb6a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_01a064cd-b632-7958-bdd4-522bd0fbbb6a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_01a064cd-b632-7958-bdd4-522bd0fbbb6a" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_01a064cd-b632-7958-bdd4-522bd0fbbb6a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_01a064cd-b632-73d4-8f46-ea5a4cae9867" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_01a064cd-b632-7958-bdd4-522bd0fbbb6a" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_01a064cd-b632-73d4-8f46-ea5a4cae9867" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_LiabilityClassifiedEarnoutSharesMember_01a064cd-b632-7108-bd01-5c24c4384337" xlink:href="innv-20260930.xsd#innv_LiabilityClassifiedEarnoutSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_01a064cd-b632-73d4-8f46-ea5a4cae9867" xlink:to="loc_innv_LiabilityClassifiedEarnoutSharesMember_01a064cd-b632-7108-bd01-5c24c4384337" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_A2024WTIWarrantMember_01a064cd-b632-7c22-bbcb-fd00e9e7455b" xlink:href="innv-20260930.xsd#innv_A2024WTIWarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_01a064cd-b632-73d4-8f46-ea5a4cae9867" xlink:to="loc_innv_A2024WTIWarrantMember_01a064cd-b632-7c22-bbcb-fd00e9e7455b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_A2025WTIWarrantMember_01a064cd-b632-71a0-b2b0-a720dac419e6" xlink:href="innv-20260930.xsd#innv_A2025WTIWarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_01a064cd-b632-73d4-8f46-ea5a4cae9867" xlink:to="loc_innv_A2025WTIWarrantMember_01a064cd-b632-71a0-b2b0-a720dac419e6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_01a064cd-b632-7152-b6bb-428ff33402ea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_01a064cd-b632-7c5a-9549-faab1895288e" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_01a064cd-b632-7152-b6bb-428ff33402ea" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityIssues_01a064cd-b632-7ecc-9e37-f1fbdcc6274b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_01a064cd-b632-7c5a-9549-faab1895288e" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityIssues_01a064cd-b632-7ecc-9e37-f1fbdcc6274b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements_01a064cd-b632-70a8-bd71-bfec0ae4e728" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_01a064cd-b632-7c5a-9549-faab1895288e" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements_01a064cd-b632-70a8-bd71-bfec0ae4e728" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings_01a064cd-b632-7e34-b5d4-d857e69b64b7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_01a064cd-b632-7c5a-9549-faab1895288e" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings_01a064cd-b632-7e34-b5d4-d857e69b64b7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_01a064cd-b632-777a-b126-e4aac655727a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/FairValueChangesinFairValueofLevel3DerivativeLiabilitiesDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#FairValueChangesinFairValueofLevel3DerivativeLiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/FairValueChangesinFairValueofLevel3DerivativeLiabilitiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_01a064cd-b632-75e4-a44a-cc8c081bf800" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationTable_01a064cd-b632-79b8-bf5c-216fdc61ff1f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_01a064cd-b632-75e4-a44a-cc8c081bf800" xlink:to="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationTable_01a064cd-b632-79b8-bf5c-216fdc61ff1f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByLiabilityClassAxis_01a064cd-b632-7818-9e73-00ffeb7bd607" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByLiabilityClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationTable_01a064cd-b632-79b8-bf5c-216fdc61ff1f" xlink:to="loc_us-gaap_FairValueByLiabilityClassAxis_01a064cd-b632-7818-9e73-00ffeb7bd607" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_01a064cd-b632-7818-9e73-00ffeb7bd607_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_01a064cd-b632-7818-9e73-00ffeb7bd607" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_01a064cd-b632-7818-9e73-00ffeb7bd607_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_01a064cd-b632-768e-9e22-4c422db93c51" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_01a064cd-b632-7818-9e73-00ffeb7bd607" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_01a064cd-b632-768e-9e22-4c422db93c51" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmbeddedDerivativeFinancialInstrumentsMember_01a064cd-b632-7cf8-bce2-856dbea50211" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmbeddedDerivativeFinancialInstrumentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_01a064cd-b632-768e-9e22-4c422db93c51" xlink:to="loc_us-gaap_EmbeddedDerivativeFinancialInstrumentsMember_01a064cd-b632-7cf8-bce2-856dbea50211" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-71a9-b62e-9d79102afff1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationTable_01a064cd-b632-79b8-bf5c-216fdc61ff1f" xlink:to="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-71a9-b62e-9d79102afff1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-71a9-b62e-9d79102afff1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-71a9-b62e-9d79102afff1" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-71a9-b62e-9d79102afff1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-774e-b427-481a6a71f8f1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-71a9-b62e-9d79102afff1" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-774e-b427-481a6a71f8f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ConvertibleDebenturesMember_01a064cd-b632-7e1c-a494-15c0ca07d764" xlink:href="innv-20260930.xsd#innv_ConvertibleDebenturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-774e-b427-481a6a71f8f1" xlink:to="loc_innv_ConvertibleDebenturesMember_01a064cd-b632-7e1c-a494-15c0ca07d764" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward_01a064cd-b632-7a38-b97c-de28fd894896" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_01a064cd-b632-75e4-a44a-cc8c081bf800" xlink:to="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward_01a064cd-b632-7a38-b97c-de28fd894896" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs_01a064cd-b632-74d4-9575-3a337eff2152" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward_01a064cd-b632-7a38-b97c-de28fd894896" xlink:to="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs_01a064cd-b632-74d4-9575-3a337eff2152" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues_01a064cd-b632-7318-a052-f9ca278087ba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward_01a064cd-b632-7a38-b97c-de28fd894896" xlink:to="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationIssues_01a064cd-b632-7318-a052-f9ca278087ba" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements_01a064cd-b632-7b54-9307-037b23307736" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward_01a064cd-b632-7a38-b97c-de28fd894896" xlink:to="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationSettlements_01a064cd-b632-7b54-9307-037b23307736" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings_01a064cd-b632-7591-aa2f-1b4173f0ff05" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputReconciliationRollForward_01a064cd-b632-7a38-b97c-de28fd894896" xlink:to="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisUnobservableInputsReconciliationGainLossIncludedInEarnings_01a064cd-b632-7591-aa2f-1b4173f0ff05" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs_01a064cd-b632-77f1-bd57-06502a8f6b28" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisWithUnobservableInputs"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/FairValueSignificantUnobservableInputsDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#FairValueSignificantUnobservableInputsDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/FairValueSignificantUnobservableInputsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_01a064cd-b632-7bf9-8e6f-fedf3eb2e57e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_01a064cd-b632-725e-940d-700f625599f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_01a064cd-b632-7bf9-8e6f-fedf3eb2e57e" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_01a064cd-b632-725e-940d-700f625599f8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_01a064cd-b632-7c03-91bf-bc3d8b2cba3d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_01a064cd-b632-725e-940d-700f625599f8" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_01a064cd-b632-7c03-91bf-bc3d8b2cba3d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-7c03-91bf-bc3d8b2cba3d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_01a064cd-b632-7c03-91bf-bc3d8b2cba3d" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-7c03-91bf-bc3d8b2cba3d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-713b-85d9-94e2a53b2e7d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_01a064cd-b632-7c03-91bf-bc3d8b2cba3d" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-713b-85d9-94e2a53b2e7d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputQuotedPriceMember_01a064cd-b632-7d8c-9ef1-52622037441d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputQuotedPriceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-713b-85d9-94e2a53b2e7d" xlink:to="loc_us-gaap_MeasurementInputQuotedPriceMember_01a064cd-b632-7d8c-9ef1-52622037441d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputExpectedTermMember_01a064cd-b632-7efd-bf8b-47f8cdf944f9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputExpectedTermMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-713b-85d9-94e2a53b2e7d" xlink:to="loc_us-gaap_MeasurementInputExpectedTermMember_01a064cd-b632-7efd-bf8b-47f8cdf944f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputSharePriceMember_01a064cd-b632-79fd-b1c1-aa6f1ba53afa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputSharePriceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-713b-85d9-94e2a53b2e7d" xlink:to="loc_us-gaap_MeasurementInputSharePriceMember_01a064cd-b632-79fd-b1c1-aa6f1ba53afa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputPriceVolatilityMember_01a064cd-b632-7567-aef0-f386cf675452" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputPriceVolatilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-713b-85d9-94e2a53b2e7d" xlink:to="loc_us-gaap_MeasurementInputPriceVolatilityMember_01a064cd-b632-7567-aef0-f386cf675452" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputRiskFreeInterestRateMember_01a064cd-b632-7ecf-89fd-47b0c3711eac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputRiskFreeInterestRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-713b-85d9-94e2a53b2e7d" xlink:to="loc_us-gaap_MeasurementInputRiskFreeInterestRateMember_01a064cd-b632-7ecf-89fd-47b0c3711eac" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_MeasurementInputRevenueRiskPremiumMember_01a064cd-b632-7918-962a-6ef750f4fbda" xlink:href="innv-20260930.xsd#innv_MeasurementInputRevenueRiskPremiumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-713b-85d9-94e2a53b2e7d" xlink:to="loc_innv_MeasurementInputRevenueRiskPremiumMember_01a064cd-b632-7918-962a-6ef750f4fbda" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_MeasurementInputRevenueVolatilityMember_01a064cd-b632-7c97-a99d-4af499fcb08b" xlink:href="innv-20260930.xsd#innv_MeasurementInputRevenueVolatilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-713b-85d9-94e2a53b2e7d" xlink:to="loc_innv_MeasurementInputRevenueVolatilityMember_01a064cd-b632-7c97-a99d-4af499fcb08b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputCreditSpreadMember_01a064cd-b632-7dfb-8f30-599ae7bf3829" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputCreditSpreadMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-713b-85d9-94e2a53b2e7d" xlink:to="loc_us-gaap_MeasurementInputCreditSpreadMember_01a064cd-b632-7dfb-8f30-599ae7bf3829" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b632-718c-852c-19a8a5605229" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_01a064cd-b632-725e-940d-700f625599f8" xlink:to="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b632-718c-852c-19a8a5605229" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-718c-852c-19a8a5605229_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b632-718c-852c-19a8a5605229" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-718c-852c-19a8a5605229_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-795f-8333-fdec6aa3fd80" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b632-718c-852c-19a8a5605229" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-795f-8333-fdec6aa3fd80" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_A2024WTIWarrantMember_01a064cd-b632-79ef-9e87-db1775ba9a2d" xlink:href="innv-20260930.xsd#innv_A2024WTIWarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-795f-8333-fdec6aa3fd80" xlink:to="loc_innv_A2024WTIWarrantMember_01a064cd-b632-79ef-9e87-db1775ba9a2d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_A2025WTIWarrantMember_01a064cd-b632-75f2-bb3c-21ebce4f152b" xlink:href="innv-20260930.xsd#innv_A2025WTIWarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-795f-8333-fdec6aa3fd80" xlink:to="loc_innv_A2025WTIWarrantMember_01a064cd-b632-75f2-bb3c-21ebce4f152b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleMeasurementInput_01a064cd-b632-7d34-b9a3-08febbca4afe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtSecuritiesAvailableForSaleMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_01a064cd-b632-7bf9-8e6f-fedf3eb2e57e" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleMeasurementInput_01a064cd-b632-7d34-b9a3-08febbca4afe" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ContingentConsiderationSharesMeasurementInput_01a064cd-b632-72ea-b834-f82c1d6715a3" xlink:href="innv-20260930.xsd#innv_ContingentConsiderationSharesMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_01a064cd-b632-7bf9-8e6f-fedf3eb2e57e" xlink:to="loc_innv_ContingentConsiderationSharesMeasurementInput_01a064cd-b632-72ea-b834-f82c1d6715a3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantsAndRightsOutstandingMeasurementInput_01a064cd-b632-70dc-89f0-7aa287ee7702" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WarrantsAndRightsOutstandingMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_01a064cd-b632-7bf9-8e6f-fedf3eb2e57e" xlink:to="loc_us-gaap_WarrantsAndRightsOutstandingMeasurementInput_01a064cd-b632-70dc-89f0-7aa287ee7702" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/FairValueNarrativeDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#FairValueNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/FairValueNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_01a064cd-b632-769f-b068-69494a5bee1c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_01a064cd-b632-72ed-b3a9-eb5a516da418" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_01a064cd-b632-769f-b068-69494a5bee1c" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_01a064cd-b632-72ed-b3a9-eb5a516da418" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_01a064cd-b632-7c9e-9825-4bf6e89b4f45" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_01a064cd-b632-72ed-b3a9-eb5a516da418" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_01a064cd-b632-7c9e-9825-4bf6e89b4f45" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_01a064cd-b632-7c9e-9825-4bf6e89b4f45_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_01a064cd-b632-7c9e-9825-4bf6e89b4f45" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_01a064cd-b632-7c9e-9825-4bf6e89b4f45_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_01a064cd-b632-721c-810b-bdd11721535c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_01a064cd-b632-7c9e-9825-4bf6e89b4f45" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_01a064cd-b632-721c-810b-bdd11721535c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_AeroFlexxLLCMember_01a064cd-b632-7225-a5ea-0c0bde4ca900" xlink:href="innv-20260930.xsd#innv_AeroFlexxLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_01a064cd-b632-721c-810b-bdd11721535c" xlink:to="loc_innv_AeroFlexxLLCMember_01a064cd-b632-7225-a5ea-0c0bde4ca900" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b632-7791-b710-6a27d8df3d0a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_01a064cd-b632-72ed-b3a9-eb5a516da418" xlink:to="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b632-7791-b710-6a27d8df3d0a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-7791-b710-6a27d8df3d0a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b632-7791-b710-6a27d8df3d0a" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-7791-b710-6a27d8df3d0a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-79e9-a396-f849b2f9a55e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b632-7791-b710-6a27d8df3d0a" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-79e9-a396-f849b2f9a55e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_A2025WTIWarrantsMember_01a064cd-b632-7be9-b1a6-3a25b8fd1d74" xlink:href="innv-20260930.xsd#innv_A2025WTIWarrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-79e9-a396-f849b2f9a55e" xlink:to="loc_innv_A2025WTIWarrantsMember_01a064cd-b632-7be9-b1a6-3a25b8fd1d74" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_01a064cd-b632-7346-8a84-fb4c216e1e21" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_01a064cd-b632-72ed-b3a9-eb5a516da418" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_01a064cd-b632-7346-8a84-fb4c216e1e21" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-7346-8a84-fb4c216e1e21_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_01a064cd-b632-7346-8a84-fb4c216e1e21" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-7346-8a84-fb4c216e1e21_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-712a-8a5b-220ac6fc02cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_01a064cd-b632-7346-8a84-fb4c216e1e21" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-712a-8a5b-220ac6fc02cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputSharePriceMember_01a064cd-b632-76b3-ae3d-52e008f87346" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputSharePriceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-712a-8a5b-220ac6fc02cb" xlink:to="loc_us-gaap_MeasurementInputSharePriceMember_01a064cd-b632-76b3-ae3d-52e008f87346" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputPriceVolatilityMember_01a064cd-b632-74f1-85eb-ce7f3bf51122" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputPriceVolatilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-712a-8a5b-220ac6fc02cb" xlink:to="loc_us-gaap_MeasurementInputPriceVolatilityMember_01a064cd-b632-74f1-85eb-ce7f3bf51122" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputCreditSpreadMember_01a064cd-b632-7780-aeaf-6564430704cc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputCreditSpreadMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-712a-8a5b-220ac6fc02cb" xlink:to="loc_us-gaap_MeasurementInputCreditSpreadMember_01a064cd-b632-7780-aeaf-6564430704cc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_MeasurementInputDebtYieldMember_01a064cd-b632-785b-b4c0-67a033626f85" xlink:href="innv-20260930.xsd#innv_MeasurementInputDebtYieldMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-712a-8a5b-220ac6fc02cb" xlink:to="loc_innv_MeasurementInputDebtYieldMember_01a064cd-b632-785b-b4c0-67a033626f85" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputRiskFreeInterestRateMember_01a08bb7-4be5-7eeb-b78f-1d62c4dbd209" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputRiskFreeInterestRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-712a-8a5b-220ac6fc02cb" xlink:to="loc_us-gaap_MeasurementInputRiskFreeInterestRateMember_01a08bb7-4be5-7eeb-b78f-1d62c4dbd209" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputExpectedTermMember_01a08bb7-4be5-777b-8b98-b001e17216c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MeasurementInputExpectedTermMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_01a064cd-b632-712a-8a5b-220ac6fc02cb" xlink:to="loc_us-gaap_MeasurementInputExpectedTermMember_01a08bb7-4be5-777b-8b98-b001e17216c7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ConversionOfDebtSecuritiesAvailableForSaleToEquityMethodInvestments_01a064cd-b632-7be3-98de-2346d196ee3b" xlink:href="innv-20260930.xsd#innv_ConversionOfDebtSecuritiesAvailableForSaleToEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_01a064cd-b632-769f-b068-69494a5bee1c" xlink:to="loc_innv_ConversionOfDebtSecuritiesAvailableForSaleToEquityMethodInvestments_01a064cd-b632-7be3-98de-2346d196ee3b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantsAndRightsOutstandingMeasurementInput_01a064cd-b632-767a-8d29-7f7a5077fc26" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WarrantsAndRightsOutstandingMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_01a064cd-b632-769f-b068-69494a5bee1c" xlink:to="loc_us-gaap_WarrantsAndRightsOutstandingMeasurementInput_01a064cd-b632-767a-8d29-7f7a5077fc26" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmbeddedDerivativeLiabilityMeasurementInput_01a064cd-b632-7b13-9b49-15bc19ece865" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmbeddedDerivativeLiabilityMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_01a064cd-b632-769f-b068-69494a5bee1c" xlink:to="loc_us-gaap_EmbeddedDerivativeLiabilityMeasurementInput_01a064cd-b632-7b13-9b49-15bc19ece865" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/BorrowingsComponentsDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#BorrowingsComponentsDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/BorrowingsComponentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-7291-9631-00063f3e2673" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-75db-b240-bfd9e274bf96" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-7291-9631-00063f3e2673" xlink:to="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-75db-b240-bfd9e274bf96" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-72f5-b70f-16e1e24fa164" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-75db-b240-bfd9e274bf96" xlink:to="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-72f5-b70f-16e1e24fa164" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-72f5-b70f-16e1e24fa164_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-72f5-b70f-16e1e24fa164" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-72f5-b70f-16e1e24fa164_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-7e2e-8b9e-ad032efc5f8c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-72f5-b70f-16e1e24fa164" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-7e2e-8b9e-ad032efc5f8c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_Series1PromissoryNotesMember_01a064cd-b632-78a6-8555-3a0379109ed3" xlink:href="innv-20260930.xsd#innv_Series1PromissoryNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-7e2e-8b9e-ad032efc5f8c" xlink:to="loc_innv_Series1PromissoryNotesMember_01a064cd-b632-78a6-8555-3a0379109ed3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_RelatedPartyConvertibleNotesMember_01a064cd-b632-75b5-afb4-768767573927" xlink:href="innv-20260930.xsd#innv_RelatedPartyConvertibleNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-7e2e-8b9e-ad032efc5f8c" xlink:to="loc_innv_RelatedPartyConvertibleNotesMember_01a064cd-b632-75b5-afb4-768767573927" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ConvertibleDebenturesMember_01a064cd-b632-7df9-9c2c-0be1997363ca" xlink:href="innv-20260930.xsd#innv_ConvertibleDebenturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-7e2e-8b9e-ad032efc5f8c" xlink:to="loc_innv_ConvertibleDebenturesMember_01a064cd-b632-7df9-9c2c-0be1997363ca" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TermConvertibleNotesMember_01a064cd-b632-7a24-a4e1-2f5e4541e6ca" xlink:href="innv-20260930.xsd#innv_TermConvertibleNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-7e2e-8b9e-ad032efc5f8c" xlink:to="loc_innv_TermConvertibleNotesMember_01a064cd-b632-7a24-a4e1-2f5e4541e6ca" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_WTIFacilityMember_01a064cd-b632-72e4-bf1b-65e20fb7adb8" xlink:href="innv-20260930.xsd#innv_WTIFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-7e2e-8b9e-ad032efc5f8c" xlink:to="loc_innv_WTIFacilityMember_01a064cd-b632-72e4-bf1b-65e20fb7adb8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleNotesPayableMember_01a064cd-b632-77bc-ad49-6c364b807d36" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-7e2e-8b9e-ad032efc5f8c" xlink:to="loc_us-gaap_ConvertibleNotesPayableMember_01a064cd-b632-77bc-ad49-6c364b807d36" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b632-78de-99c4-0bfc56cc734c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-75db-b240-bfd9e274bf96" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b632-78de-99c4-0bfc56cc734c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-78de-99c4-0bfc56cc734c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b632-78de-99c4-0bfc56cc734c" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-78de-99c4-0bfc56cc734c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-7e71-828c-9f7a4b26c65c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b632-78de-99c4-0bfc56cc734c" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-7e71-828c-9f7a4b26c65c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember_01a064cd-b632-734d-9ca2-fbff43a4dd88" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesPayableOtherPayablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-7e71-828c-9f7a4b26c65c" xlink:to="loc_us-gaap_NotesPayableOtherPayablesMember_01a064cd-b632-734d-9ca2-fbff43a4dd88" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_01a064cd-b632-7e6f-b480-f7abadd6561c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-7e71-828c-9f7a4b26c65c" xlink:to="loc_us-gaap_ConvertibleDebtMember_01a064cd-b632-7e6f-b480-f7abadd6561c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_01a064cd-b632-75b1-90c5-be06d08f1342" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-7e71-828c-9f7a4b26c65c" xlink:to="loc_us-gaap_SecuredDebtMember_01a064cd-b632-75b1-90c5-be06d08f1342" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a064cd-b632-7ded-a9f8-c85466731baf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-75db-b240-bfd9e274bf96" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a064cd-b632-7ded-a9f8-c85466731baf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a064cd-b632-7ded-a9f8-c85466731baf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a064cd-b632-7ded-a9f8-c85466731baf" xlink:to="loc_us-gaap_RelatedPartyDomain_01a064cd-b632-7ded-a9f8-c85466731baf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a064cd-b632-7706-8ecf-880e226d9028" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a064cd-b632-7ded-a9f8-c85466731baf" xlink:to="loc_us-gaap_RelatedPartyDomain_01a064cd-b632-7706-8ecf-880e226d9028" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonrelatedPartyMember_01a064cd-b632-756d-9124-d24a4d93de9b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NonrelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_01a064cd-b632-7706-8ecf-880e226d9028" xlink:to="loc_us-gaap_NonrelatedPartyMember_01a064cd-b632-756d-9124-d24a4d93de9b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_01a064cd-b632-7d7e-9590-041a76ef1786" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_01a064cd-b632-7706-8ecf-880e226d9028" xlink:to="loc_us-gaap_RelatedPartyMember_01a064cd-b632-7d7e-9590-041a76ef1786" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_01a064cd-b632-7036-b31e-3ee763fb9e36" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-75db-b240-bfd9e274bf96" xlink:to="loc_srt_RangeAxis_01a064cd-b632-7036-b31e-3ee763fb9e36" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_01a064cd-b632-7036-b31e-3ee763fb9e36_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_01a064cd-b632-7036-b31e-3ee763fb9e36" xlink:to="loc_srt_RangeMember_01a064cd-b632-7036-b31e-3ee763fb9e36_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_01a064cd-b632-7078-8b27-420ea823ceb0" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_01a064cd-b632-7036-b31e-3ee763fb9e36" xlink:to="loc_srt_RangeMember_01a064cd-b632-7078-8b27-420ea823ceb0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_01a064cd-b632-75bc-a4be-39b0b4a2ec4e" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_01a064cd-b632-7078-8b27-420ea823ceb0" xlink:to="loc_srt_MinimumMember_01a064cd-b632-75bc-a4be-39b0b4a2ec4e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_01a064cd-b632-7087-b829-863b17912f69" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_01a064cd-b632-7078-8b27-420ea823ceb0" xlink:to="loc_srt_MaximumMember_01a064cd-b632-7087-b829-863b17912f69" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_01a064cd-b632-7e18-9488-070ac972e186" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-7291-9631-00063f3e2673" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_01a064cd-b632-7e18-9488-070ac972e186" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_01a064cd-b632-73da-bbbb-2861242a8458" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-7291-9631-00063f3e2673" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_01a064cd-b632-73da-bbbb-2861242a8458" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscount_01a064cd-b632-71b2-a5b8-0d5bed2378f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentUnamortizedDiscount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-7291-9631-00063f3e2673" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscount_01a064cd-b632-71b2-a5b8-0d5bed2378f3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrent_01a064cd-b632-70bf-b519-042a21ba2e82" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-7291-9631-00063f3e2673" xlink:to="loc_us-gaap_LongTermDebtCurrent_01a064cd-b632-70bf-b519-042a21ba2e82" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_01a064cd-b632-7b7f-9dc4-bdf49138c92c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-7291-9631-00063f3e2673" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_01a064cd-b632-7b7f-9dc4-bdf49138c92c" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/BorrowingsNarrativeDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#BorrowingsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/BorrowingsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-7406-870c-2f292e858178" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-7406-870c-2f292e858178" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-7daf-9651-e159c31d45ac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-7406-870c-2f292e858178" xlink:to="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-7daf-9651-e159c31d45ac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-7daf-9651-e159c31d45ac_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-7daf-9651-e159c31d45ac" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-7daf-9651-e159c31d45ac_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-73b1-8216-2b5cd4f743b3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-7daf-9651-e159c31d45ac" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-73b1-8216-2b5cd4f743b3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_Series1PromissoryNotesMember_01a064cd-b632-7d5f-8f7f-f5563a39e94f" xlink:href="innv-20260930.xsd#innv_Series1PromissoryNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-73b1-8216-2b5cd4f743b3" xlink:to="loc_innv_Series1PromissoryNotesMember_01a064cd-b632-7d5f-8f7f-f5563a39e94f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_Series1PromissoryNotesFirstTermExtensionMember_01a064cd-b632-7f56-a4a0-46f5e6872c3b" xlink:href="innv-20260930.xsd#innv_Series1PromissoryNotesFirstTermExtensionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_innv_Series1PromissoryNotesMember_01a064cd-b632-7d5f-8f7f-f5563a39e94f" xlink:to="loc_innv_Series1PromissoryNotesFirstTermExtensionMember_01a064cd-b632-7f56-a4a0-46f5e6872c3b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_Series1PromissoryNotesSecondTermExtensionMember_01a064cd-b632-7b4e-a28b-25c245948ae0" xlink:href="innv-20260930.xsd#innv_Series1PromissoryNotesSecondTermExtensionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_innv_Series1PromissoryNotesMember_01a064cd-b632-7d5f-8f7f-f5563a39e94f" xlink:to="loc_innv_Series1PromissoryNotesSecondTermExtensionMember_01a064cd-b632-7b4e-a28b-25c245948ae0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_WTIFacilityMember_01a064cd-b632-79e2-9b64-a8be21e23f50" xlink:href="innv-20260930.xsd#innv_WTIFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-73b1-8216-2b5cd4f743b3" xlink:to="loc_innv_WTIFacilityMember_01a064cd-b632-79e2-9b64-a8be21e23f50" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ConvertibleDebenturesMember_01a064cd-b632-7a66-a9f3-7bb38b69d41b" xlink:href="innv-20260930.xsd#innv_ConvertibleDebenturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-73b1-8216-2b5cd4f743b3" xlink:to="loc_innv_ConvertibleDebenturesMember_01a064cd-b632-7a66-a9f3-7bb38b69d41b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ExistingConvertibleDebenturesMember_01a064cd-b632-73e1-9b44-ce10c7a29995" xlink:href="innv-20260930.xsd#innv_ExistingConvertibleDebenturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_innv_ConvertibleDebenturesMember_01a064cd-b632-7a66-a9f3-7bb38b69d41b" xlink:to="loc_innv_ExistingConvertibleDebenturesMember_01a064cd-b632-73e1-9b44-ce10c7a29995" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_NewConvertibleDebenturesMember_01a064cd-b632-7b0a-b560-a776bffa0e46" xlink:href="innv-20260930.xsd#innv_NewConvertibleDebenturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_innv_ConvertibleDebenturesMember_01a064cd-b632-7a66-a9f3-7bb38b69d41b" xlink:to="loc_innv_NewConvertibleDebenturesMember_01a064cd-b632-7b0a-b560-a776bffa0e46" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TermConvertibleNotesMember_01a064cd-b632-78fc-9890-6c1391f47f1d" xlink:href="innv-20260930.xsd#innv_TermConvertibleNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-73b1-8216-2b5cd4f743b3" xlink:to="loc_innv_TermConvertibleNotesMember_01a064cd-b632-78fc-9890-6c1391f47f1d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_RelatedPartyTermConvertibleNotesMember_01a064cd-b632-721f-a43a-37f29c47eacf" xlink:href="innv-20260930.xsd#innv_RelatedPartyTermConvertibleNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-73b1-8216-2b5cd4f743b3" xlink:to="loc_innv_RelatedPartyTermConvertibleNotesMember_01a064cd-b632-721f-a43a-37f29c47eacf" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_RelatedPartyConvertibleNotesMember_01a064cd-b632-727f-a517-1738c22fd98e" xlink:href="innv-20260930.xsd#innv_RelatedPartyConvertibleNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-73b1-8216-2b5cd4f743b3" xlink:to="loc_innv_RelatedPartyConvertibleNotesMember_01a064cd-b632-727f-a517-1738c22fd98e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b632-7693-812f-82fc0ec32f37" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-7406-870c-2f292e858178" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b632-7693-812f-82fc0ec32f37" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-7693-812f-82fc0ec32f37_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b632-7693-812f-82fc0ec32f37" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-7693-812f-82fc0ec32f37_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-7bcd-94ad-36e47d070b39" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b632-7693-812f-82fc0ec32f37" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-7bcd-94ad-36e47d070b39" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember_01a064cd-b632-7e9b-8a3a-272384b3f7c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesPayableOtherPayablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-7bcd-94ad-36e47d070b39" xlink:to="loc_us-gaap_NotesPayableOtherPayablesMember_01a064cd-b632-7e9b-8a3a-272384b3f7c7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_01a064cd-b632-74c4-bfc8-3b8ceb477abf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-7bcd-94ad-36e47d070b39" xlink:to="loc_us-gaap_SecuredDebtMember_01a064cd-b632-74c4-bfc8-3b8ceb477abf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_01a064cd-b632-7599-b794-743f0f78b597" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-7bcd-94ad-36e47d070b39" xlink:to="loc_us-gaap_ConvertibleDebtMember_01a064cd-b632-7599-b794-743f0f78b597" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_01a064cd-b632-7ba3-a3c7-ed4e214863d7" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-7406-870c-2f292e858178" xlink:to="loc_srt_RangeAxis_01a064cd-b632-7ba3-a3c7-ed4e214863d7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_01a064cd-b632-7ba3-a3c7-ed4e214863d7_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_01a064cd-b632-7ba3-a3c7-ed4e214863d7" xlink:to="loc_srt_RangeMember_01a064cd-b632-7ba3-a3c7-ed4e214863d7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_01a064cd-b632-78ac-b768-35fdf4f1eb06" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_01a064cd-b632-7ba3-a3c7-ed4e214863d7" xlink:to="loc_srt_RangeMember_01a064cd-b632-78ac-b768-35fdf4f1eb06" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_01a064cd-b632-7e90-8f2a-3c7757a0c960" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_01a064cd-b632-78ac-b768-35fdf4f1eb06" xlink:to="loc_srt_MinimumMember_01a064cd-b632-7e90-8f2a-3c7757a0c960" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_01a064cd-b632-7df2-9cb0-5aa1f0c1a313" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_01a064cd-b632-78ac-b768-35fdf4f1eb06" xlink:to="loc_srt_MaximumMember_01a064cd-b632-7df2-9cb0-5aa1f0c1a313" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b632-7e3f-b8a1-76908a46e149" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-7406-870c-2f292e858178" xlink:to="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b632-7e3f-b8a1-76908a46e149" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-7e3f-b8a1-76908a46e149_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b632-7e3f-b8a1-76908a46e149" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-7e3f-b8a1-76908a46e149_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-7fe3-ad74-aafb56ba8c13" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b632-7e3f-b8a1-76908a46e149" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-7fe3-ad74-aafb56ba8c13" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_A2025WTIWarrantMember_01a064cd-b632-7f64-ab35-d7408fef5168" xlink:href="innv-20260930.xsd#innv_A2025WTIWarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b632-7fe3-ad74-aafb56ba8c13" xlink:to="loc_innv_A2025WTIWarrantMember_01a064cd-b632-7f64-ab35-d7408fef5168" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockAxis_01a064cd-b632-70a8-a150-d02d8a76372b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-7406-870c-2f292e858178" xlink:to="loc_us-gaap_SubsidiarySaleOfStockAxis_01a064cd-b632-70a8-a150-d02d8a76372b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_01a064cd-b632-70a8-a150-d02d8a76372b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_01a064cd-b632-70a8-a150-d02d8a76372b" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_01a064cd-b632-70a8-a150-d02d8a76372b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_01a064cd-b632-78f7-8dd7-3890f7e41fdb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_01a064cd-b632-70a8-a150-d02d8a76372b" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_01a064cd-b632-78f7-8dd7-3890f7e41fdb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_StandbyEquityPurchaseAgreementMember_01a064cd-b632-7c5e-b0f1-49a3ff713a8a" xlink:href="innv-20260930.xsd#innv_StandbyEquityPurchaseAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain_01a064cd-b632-78f7-8dd7-3890f7e41fdb" xlink:to="loc_innv_StandbyEquityPurchaseAgreementMember_01a064cd-b632-7c5e-b0f1-49a3ff713a8a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_DebtInstrumentMaximumFaceAmount_01a064cd-b632-76fd-a358-f27eb4056246" xlink:href="innv-20260930.xsd#innv_DebtInstrumentMaximumFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_innv_DebtInstrumentMaximumFaceAmount_01a064cd-b632-76fd-a358-f27eb4056246" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_01a064cd-b632-7a80-9b19-983cb5f23245" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_01a064cd-b632-7a80-9b19-983cb5f23245" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_01a064cd-b632-7160-879c-00c46c77725a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_us-gaap_DebtInstrumentTerm_01a064cd-b632-7160-879c-00c46c77725a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_01a064cd-b632-7094-8188-cbdb38af124a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_01a064cd-b632-7094-8188-cbdb38af124a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_DebtInstrumentNumberOfExtensionOptions_01a064cd-b632-7484-b4ad-9e53421fcc73" xlink:href="innv-20260930.xsd#innv_DebtInstrumentNumberOfExtensionOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_innv_DebtInstrumentNumberOfExtensionOptions_01a064cd-b632-7484-b4ad-9e53421fcc73" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_DebtInstrumentTermWithExtension_01a064cd-b632-732f-a454-af7226d71326" xlink:href="innv-20260930.xsd#innv_DebtInstrumentTermWithExtension"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_innv_DebtInstrumentTermWithExtension_01a064cd-b632-732f-a454-af7226d71326" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount_01a064cd-b632-78ef-9c35-56dea14b220a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount_01a064cd-b632-78ef-9c35-56dea14b220a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_DebtInstrumentNumberOfTranches_01a064cd-b632-7093-b849-de2064011e91" xlink:href="innv-20260930.xsd#innv_DebtInstrumentNumberOfTranches"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_innv_DebtInstrumentNumberOfTranches_01a064cd-b632-7093-b849-de2064011e91" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_01a064cd-b632-7929-8fe5-0c295174372d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfLongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_01a064cd-b632-7929-8fe5-0c295174372d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_DebtInstrumentPrincipalAndInterestPaymentsPeriod_01a064cd-b632-795c-9a2b-5d04b859d3cc" xlink:href="innv-20260930.xsd#innv_DebtInstrumentPrincipalAndInterestPaymentsPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_innv_DebtInstrumentPrincipalAndInterestPaymentsPeriod_01a064cd-b632-795c-9a2b-5d04b859d3cc" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_DebtInstrumentInterestOnlyPaymentsPeriod_01a064cd-b632-770f-8afe-98c0d24dd2f6" xlink:href="innv-20260930.xsd#innv_DebtInstrumentInterestOnlyPaymentsPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_innv_DebtInstrumentInterestOnlyPaymentsPeriod_01a064cd-b632-770f-8afe-98c0d24dd2f6" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_01a064cd-b632-734b-b2b2-278bacc9b247" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_01a064cd-b632-734b-b2b2-278bacc9b247" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_DebtInstrumentRemainingTermAfterInterestOnlyPeriod_01a064cd-b632-7112-b702-87d23d1f1b64" xlink:href="innv-20260930.xsd#innv_DebtInstrumentRemainingTermAfterInterestOnlyPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_innv_DebtInstrumentRemainingTermAfterInterestOnlyPeriod_01a064cd-b632-7112-b702-87d23d1f1b64" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_DebtInstrumentRequiredCashOnDeposit_01a064cd-b632-7cfc-8295-9ff50a6fbc44" xlink:href="innv-20260930.xsd#innv_DebtInstrumentRequiredCashOnDeposit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_innv_DebtInstrumentRequiredCashOnDeposit_01a064cd-b632-7cfc-8295-9ff50a6fbc44" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_01a064cd-b632-73d2-8e69-dcf37d781078" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_01a064cd-b632-73d2-8e69-dcf37d781078" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_DebtInstrumentDiscountPercentage_01a064cd-b632-7bf2-a294-852e523ce69f" xlink:href="innv-20260930.xsd#innv_DebtInstrumentDiscountPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_innv_DebtInstrumentDiscountPercentage_01a064cd-b632-7bf2-a294-852e523ce69f" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_DebtInstrumentPeriodicPaymentTerm_01a064cd-b632-7f1d-9d3f-845304a25d47" xlink:href="innv-20260930.xsd#innv_DebtInstrumentPeriodicPaymentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_innv_DebtInstrumentPeriodicPaymentTerm_01a064cd-b632-7f1d-9d3f-845304a25d47" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_DebtInstrumentPeriodicPaymentPaymentPremiumPercentage_01a064cd-b632-721d-97de-1c9ccec9bdf8" xlink:href="innv-20260930.xsd#innv_DebtInstrumentPeriodicPaymentPaymentPremiumPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_innv_DebtInstrumentPeriodicPaymentPaymentPremiumPercentage_01a064cd-b632-721d-97de-1c9ccec9bdf8" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightOutstanding_01a064cd-b632-7556-81df-f3d9f670bb08" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_us-gaap_ClassOfWarrantOrRightOutstanding_01a064cd-b632-7556-81df-f3d9f670bb08" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_01a064cd-b632-79fa-81d0-15c66119f44a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_01a064cd-b632-79fa-81d0-15c66119f44a" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_01a064cd-b632-79db-a29b-fd1e0811dca6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_01a064cd-b632-79db-a29b-fd1e0811dca6" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_01a064cd-b632-76c9-9f88-165c2fc02225" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentConvertibleConversionPrice1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_01a064cd-b632-76c9-9f88-165c2fc02225" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_DebtInstrumentFloorPrice_01a064cd-b632-7f3b-b9de-a9eb5a05969e" xlink:href="innv-20260930.xsd#innv_DebtInstrumentFloorPrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_innv_DebtInstrumentFloorPrice_01a064cd-b632-7f3b-b9de-a9eb5a05969e" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentPeriodicPayment_01a064cd-b632-7d10-9a84-b657812994b2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentPeriodicPayment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_us-gaap_DebtInstrumentPeriodicPayment_01a064cd-b632-7d10-9a84-b657812994b2" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_DebtInstrumentPeriodicPaymentUnderExchangeCapPercentage_01a064cd-b632-79fa-9f73-cc7e33ccefc4" xlink:href="innv-20260930.xsd#innv_DebtInstrumentPeriodicPaymentUnderExchangeCapPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_innv_DebtInstrumentPeriodicPaymentUnderExchangeCapPercentage_01a064cd-b632-79fa-9f73-cc7e33ccefc4" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromConvertibleDebt_01a064cd-b632-7c5e-b7d7-4de1c9ecca5e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromConvertibleDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_us-gaap_ProceedsFromConvertibleDebt_01a064cd-b632-7c5e-b7d7-4de1c9ecca5e" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_01a064cd-b632-7103-b5cd-ecccb84b81e2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities_01a064cd-b632-7103-b5cd-ecccb84b81e2" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfDebt_01a064cd-b632-7bf2-9d27-3e996b6deba7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RepaymentsOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_us-gaap_RepaymentsOfDebt_01a064cd-b632-7bf2-9d27-3e996b6deba7" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebt_01a064cd-b632-7787-b3e1-4b5bb2eafbc6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-77b6-b9e0-ed78d5eadce9" xlink:to="loc_us-gaap_InterestExpenseDebt_01a064cd-b632-7787-b3e1-4b5bb2eafbc6" xlink:type="arc" order="28"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/BorrowingsDebtExtensionsDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#BorrowingsDebtExtensionsDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/BorrowingsDebtExtensionsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-7ce3-9085-bc6a8d3f3e93" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-7048-9fa5-0c81d76e1985" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-7ce3-9085-bc6a8d3f3e93" xlink:to="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-7048-9fa5-0c81d76e1985" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-72ec-91e3-d636863c4689" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-7048-9fa5-0c81d76e1985" xlink:to="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-72ec-91e3-d636863c4689" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-72ec-91e3-d636863c4689_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-72ec-91e3-d636863c4689" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-72ec-91e3-d636863c4689_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-7634-ae08-9600d74be8f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-72ec-91e3-d636863c4689" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-7634-ae08-9600d74be8f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_Series1PromissoryNotesSecondTermExtensionMember_01a064cd-b632-7c66-be20-da9906a03942" xlink:href="innv-20260930.xsd#innv_Series1PromissoryNotesSecondTermExtensionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-7634-ae08-9600d74be8f3" xlink:to="loc_innv_Series1PromissoryNotesSecondTermExtensionMember_01a064cd-b632-7c66-be20-da9906a03942" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b632-7963-b09d-7327f08ed8c3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-7048-9fa5-0c81d76e1985" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b632-7963-b09d-7327f08ed8c3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-7963-b09d-7327f08ed8c3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b632-7963-b09d-7327f08ed8c3" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-7963-b09d-7327f08ed8c3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-707b-b751-d8c3c30310cc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b632-7963-b09d-7327f08ed8c3" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-707b-b751-d8c3c30310cc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember_01a064cd-b632-7af1-9cd2-54d6a82da345" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesPayableOtherPayablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-707b-b751-d8c3c30310cc" xlink:to="loc_us-gaap_NotesPayableOtherPayablesMember_01a064cd-b632-7af1-9cd2-54d6a82da345" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_DebtInstrumentFaceAmountExtendedMaturity_01a064cd-b632-7b39-aad1-e1f0c92f4878" xlink:href="innv-20260930.xsd#innv_DebtInstrumentFaceAmountExtendedMaturity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-7ce3-9085-bc6a8d3f3e93" xlink:to="loc_innv_DebtInstrumentFaceAmountExtendedMaturity_01a064cd-b632-7b39-aad1-e1f0c92f4878" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/BorrowingsInterestExpenseDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#BorrowingsInterestExpenseDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/BorrowingsInterestExpenseDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-770c-9c6b-7c29df4ccb4d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-7896-90fc-6997e5743902" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-770c-9c6b-7c29df4ccb4d" xlink:to="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-7896-90fc-6997e5743902" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-7202-b7db-89428e9fc822" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-7896-90fc-6997e5743902" xlink:to="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-7202-b7db-89428e9fc822" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-7202-b7db-89428e9fc822_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-7202-b7db-89428e9fc822" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-7202-b7db-89428e9fc822_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-75b8-bed3-7c7b3d56aa79" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a064cd-b632-7202-b7db-89428e9fc822" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-75b8-bed3-7c7b3d56aa79" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_Series1PromissoryNotesMember_01a064cd-b632-7554-b75e-546248ac6bc0" xlink:href="innv-20260930.xsd#innv_Series1PromissoryNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-75b8-bed3-7c7b3d56aa79" xlink:to="loc_innv_Series1PromissoryNotesMember_01a064cd-b632-7554-b75e-546248ac6bc0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_WTIFacilityMember_01a064cd-b632-7fe3-8da4-ac9b8e1f9709" xlink:href="innv-20260930.xsd#innv_WTIFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-75b8-bed3-7c7b3d56aa79" xlink:to="loc_innv_WTIFacilityMember_01a064cd-b632-7fe3-8da4-ac9b8e1f9709" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ConvertibleDebenturesMember_01a064cd-b632-7c07-b98e-9ab22396ba25" xlink:href="innv-20260930.xsd#innv_ConvertibleDebenturesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b632-75b8-bed3-7c7b3d56aa79" xlink:to="loc_innv_ConvertibleDebenturesMember_01a064cd-b632-7c07-b98e-9ab22396ba25" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b632-762a-9df2-66f04f2c6ad1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a064cd-b632-7896-90fc-6997e5743902" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b632-762a-9df2-66f04f2c6ad1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-762a-9df2-66f04f2c6ad1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b632-762a-9df2-66f04f2c6ad1" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-762a-9df2-66f04f2c6ad1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-7e49-b621-105f1597f5a2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b632-762a-9df2-66f04f2c6ad1" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-7e49-b621-105f1597f5a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember_01a064cd-b632-7115-93a3-93b811faa0e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesPayableOtherPayablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-7e49-b621-105f1597f5a2" xlink:to="loc_us-gaap_NotesPayableOtherPayablesMember_01a064cd-b632-7115-93a3-93b811faa0e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_01a064cd-b632-7810-9b58-2f8167f4a03f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-7e49-b621-105f1597f5a2" xlink:to="loc_us-gaap_SecuredDebtMember_01a064cd-b632-7810-9b58-2f8167f4a03f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_01a064cd-b632-7502-a315-306bf333fb07" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b632-7e49-b621-105f1597f5a2" xlink:to="loc_us-gaap_ConvertibleDebtMember_01a064cd-b632-7502-a315-306bf333fb07" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebtExcludingAmortization_01a064cd-b632-7391-a566-ac7922432883" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseDebtExcludingAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-770c-9c6b-7c29df4ccb4d" xlink:to="loc_us-gaap_InterestExpenseDebtExcludingAmortization_01a064cd-b632-7391-a566-ac7922432883" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfFinancingCosts_01a064cd-b632-74f6-ae17-0c07d84729d2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AmortizationOfFinancingCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-770c-9c6b-7c29df4ccb4d" xlink:to="loc_us-gaap_AmortizationOfFinancingCosts_01a064cd-b632-74f6-ae17-0c07d84729d2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebt_01a064cd-b632-7179-af53-f610a63c13e1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a064cd-b632-770c-9c6b-7c29df4ccb4d" xlink:to="loc_us-gaap_InterestExpenseDebt_01a064cd-b632-7179-af53-f610a63c13e1" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/PropertyPlantandEquipmentScheduleofPropertyPlantandEquipmentDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#PropertyPlantandEquipmentScheduleofPropertyPlantandEquipmentDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/PropertyPlantandEquipmentScheduleofPropertyPlantandEquipmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_01a064cd-b632-7db4-a2e9-8fbe4e4d203e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_01a064cd-b632-7a2e-9324-2a895f1193a8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_01a064cd-b632-7db4-a2e9-8fbe4e4d203e" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_01a064cd-b632-7a2e-9324-2a895f1193a8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_01a064cd-b632-780e-bcb9-ee4a2e93eff3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_01a064cd-b632-7a2e-9324-2a895f1193a8" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_01a064cd-b632-780e-bcb9-ee4a2e93eff3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a064cd-b632-780e-bcb9-ee4a2e93eff3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_01a064cd-b632-780e-bcb9-ee4a2e93eff3" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a064cd-b632-780e-bcb9-ee4a2e93eff3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a064cd-b632-71be-bec2-babf5dcaae9c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_01a064cd-b632-780e-bcb9-ee4a2e93eff3" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a064cd-b632-71be-bec2-babf5dcaae9c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_01a064cd-b632-7b4e-bc71-d63830226729" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LeaseholdImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a064cd-b632-71be-bec2-babf5dcaae9c" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_01a064cd-b632-7b4e-bc71-d63830226729" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MachineryAndEquipmentMember_01a064cd-b632-7751-9ee9-5904e342b68e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MachineryAndEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a064cd-b632-71be-bec2-babf5dcaae9c" xlink:to="loc_us-gaap_MachineryAndEquipmentMember_01a064cd-b632-7751-9ee9-5904e342b68e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ComputerAndOfficeEquipmentMember_01a064cd-b632-750c-a72a-41a9aa697d73" xlink:href="innv-20260930.xsd#innv_ComputerAndOfficeEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a064cd-b632-71be-bec2-babf5dcaae9c" xlink:to="loc_innv_ComputerAndOfficeEquipmentMember_01a064cd-b632-750c-a72a-41a9aa697d73" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressMember_01a064cd-b632-7d1b-85e8-53e917df3fb0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConstructionInProgressMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a064cd-b632-71be-bec2-babf5dcaae9c" xlink:to="loc_us-gaap_ConstructionInProgressMember_01a064cd-b632-7d1b-85e8-53e917df3fb0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_01a064cd-b632-7e82-bc11-70dccc3fc9b5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_01a064cd-b632-7db4-a2e9-8fbe4e4d203e" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_01a064cd-b632-7e82-bc11-70dccc3fc9b5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_01a064cd-b632-793d-8509-27a81441c3ac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_01a064cd-b632-7db4-a2e9-8fbe4e4d203e" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_01a064cd-b632-793d-8509-27a81441c3ac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_01a064cd-b632-7bdc-b6ac-2e21a9ec0943" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_01a064cd-b632-7db4-a2e9-8fbe4e4d203e" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_01a064cd-b632-7bdc-b6ac-2e21a9ec0943" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/GoodwillandIntangibleAssetsOtherIntangibleAssetsNetDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#GoodwillandIntangibleAssetsOtherIntangibleAssetsNetDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/GoodwillandIntangibleAssetsOtherIntangibleAssetsNetDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_01a064cd-b632-70e5-a29e-42f382284763" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_01a064cd-b632-77b6-b04f-ff67239e7a0f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_01a064cd-b632-70e5-a29e-42f382284763" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_01a064cd-b632-77b6-b04f-ff67239e7a0f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_01a064cd-b632-72d6-a36d-c829d941e01e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_01a064cd-b632-77b6-b04f-ff67239e7a0f" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_01a064cd-b632-72d6-a36d-c829d941e01e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a064cd-b632-72d6-a36d-c829d941e01e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_01a064cd-b632-72d6-a36d-c829d941e01e" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a064cd-b632-72d6-a36d-c829d941e01e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a064cd-b632-75db-98ba-77aa1da54373" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_01a064cd-b632-72d6-a36d-c829d941e01e" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a064cd-b632-75db-98ba-77aa1da54373" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeNamesMember_01a064cd-b632-7d36-b53a-345497b7406d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a064cd-b632-75db-98ba-77aa1da54373" xlink:to="loc_us-gaap_TradeNamesMember_01a064cd-b632-7d36-b53a-345497b7406d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_01a064cd-b632-7a03-a94d-54b595693ec1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a064cd-b632-75db-98ba-77aa1da54373" xlink:to="loc_us-gaap_CustomerRelationshipsMember_01a064cd-b632-7a03-a94d-54b595693ec1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DevelopedTechnologyRightsMember_01a064cd-b632-7a4a-8088-d22ba8444d66" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DevelopedTechnologyRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a064cd-b632-75db-98ba-77aa1da54373" xlink:to="loc_us-gaap_DevelopedTechnologyRightsMember_01a064cd-b632-7a4a-8088-d22ba8444d66" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_01a064cd-b632-760c-8912-bc83f9815601" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a064cd-b632-75db-98ba-77aa1da54373" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_01a064cd-b632-760c-8912-bc83f9815601" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_01a064cd-b632-7293-8c3d-969faabb457f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_01a064cd-b632-70e5-a29e-42f382284763" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_01a064cd-b632-7293-8c3d-969faabb457f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_01a064cd-b632-7e26-969e-091be5a29e16" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_01a064cd-b632-70e5-a29e-42f382284763" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_01a064cd-b632-7e26-969e-091be5a29e16" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_01a064cd-b632-76cd-b080-7fdd62cfef7b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_01a064cd-b632-70e5-a29e-42f382284763" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_01a064cd-b632-76cd-b080-7fdd62cfef7b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_01a064cd-b632-7db8-8d74-03710a5b3c6e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_01a064cd-b632-70e5-a29e-42f382284763" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_01a064cd-b632-7db8-8d74-03710a5b3c6e" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/EarnoutSharesDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#EarnoutSharesDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/EarnoutSharesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionContingentConsiderationLineItems_01a064cd-b6c3-7f89-a43e-c560f37305c0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionContingentConsiderationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionContingentConsiderationTable_01a064cd-b632-7afb-865e-a5de63f052fd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionContingentConsiderationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionContingentConsiderationLineItems_01a064cd-b6c3-7f89-a43e-c560f37305c0" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionContingentConsiderationTable_01a064cd-b632-7afb-865e-a5de63f052fd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_01a064cd-b632-73b6-891b-532bb50b4a45" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionContingentConsiderationTable_01a064cd-b632-7afb-865e-a5de63f052fd" xlink:to="loc_srt_CounterpartyNameAxis_01a064cd-b632-73b6-891b-532bb50b4a45" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_01a064cd-b632-73b6-891b-532bb50b4a45_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_01a064cd-b632-73b6-891b-532bb50b4a45" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_01a064cd-b632-73b6-891b-532bb50b4a45_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_01a064cd-b632-72f3-9c97-2505f5abf19d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_01a064cd-b632-73b6-891b-532bb50b4a45" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_01a064cd-b632-72f3-9c97-2505f5abf19d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_InnventureMembersMember_01a064cd-b632-7738-99f0-264c1bea4e6a" xlink:href="innv-20260930.xsd#innv_InnventureMembersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_01a064cd-b632-72f3-9c97-2505f5abf19d" xlink:to="loc_innv_InnventureMembersMember_01a064cd-b632-7738-99f0-264c1bea4e6a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_SponsorMember_01a064cd-b632-7c2c-834c-74a99ded9fb9" xlink:href="innv-20260930.xsd#innv_SponsorMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_01a064cd-b632-72f3-9c97-2505f5abf19d" xlink:to="loc_innv_SponsorMember_01a064cd-b632-7c2c-834c-74a99ded9fb9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_01a064cd-b632-7b38-9e00-4c00a0adec97" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionContingentConsiderationTable_01a064cd-b632-7afb-865e-a5de63f052fd" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_01a064cd-b632-7b38-9e00-4c00a0adec97" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a064cd-b632-7b38-9e00-4c00a0adec97_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_01a064cd-b632-7b38-9e00-4c00a0adec97" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a064cd-b632-7b38-9e00-4c00a0adec97_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a064cd-b632-7af7-a6d5-520d1a5ac2b9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_01a064cd-b632-7b38-9e00-4c00a0adec97" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a064cd-b632-7af7-a6d5-520d1a5ac2b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_InnventureLLCMember_01a064cd-b632-7bdf-8ee1-7ca26a84b655" xlink:href="innv-20260930.xsd#innv_InnventureLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a064cd-b632-7af7-a6d5-520d1a5ac2b9" xlink:to="loc_innv_InnventureLLCMember_01a064cd-b632-7bdf-8ee1-7ca26a84b655" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ContingentConsiderationSharesMilestoneAxis_01a064cd-b632-7f49-bb04-894eb01cf9f7" xlink:href="innv-20260930.xsd#innv_ContingentConsiderationSharesMilestoneAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionContingentConsiderationTable_01a064cd-b632-7afb-865e-a5de63f052fd" xlink:to="loc_innv_ContingentConsiderationSharesMilestoneAxis_01a064cd-b632-7f49-bb04-894eb01cf9f7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ContingentConsiderationSharesMilestoneDomain_01a064cd-b632-7f49-bb04-894eb01cf9f7_default" xlink:href="innv-20260930.xsd#innv_ContingentConsiderationSharesMilestoneDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_innv_ContingentConsiderationSharesMilestoneAxis_01a064cd-b632-7f49-bb04-894eb01cf9f7" xlink:to="loc_innv_ContingentConsiderationSharesMilestoneDomain_01a064cd-b632-7f49-bb04-894eb01cf9f7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ContingentConsiderationSharesMilestoneDomain_01a064cd-b6c3-7c37-a83b-5722c5b86292" xlink:href="innv-20260930.xsd#innv_ContingentConsiderationSharesMilestoneDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_innv_ContingentConsiderationSharesMilestoneAxis_01a064cd-b632-7f49-bb04-894eb01cf9f7" xlink:to="loc_innv_ContingentConsiderationSharesMilestoneDomain_01a064cd-b6c3-7c37-a83b-5722c5b86292" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ContingentConsiderationSharesMilestoneTwoMember_01a064cd-b6c3-7527-b9c7-c0799a5edd1f" xlink:href="innv-20260930.xsd#innv_ContingentConsiderationSharesMilestoneTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_innv_ContingentConsiderationSharesMilestoneDomain_01a064cd-b6c3-7c37-a83b-5722c5b86292" xlink:to="loc_innv_ContingentConsiderationSharesMilestoneTwoMember_01a064cd-b6c3-7527-b9c7-c0799a5edd1f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ContingentConsiderationSharesMilestoneOneMember_01a064cd-b6c3-7955-bf46-911a9cd4adf3" xlink:href="innv-20260930.xsd#innv_ContingentConsiderationSharesMilestoneOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_innv_ContingentConsiderationSharesMilestoneDomain_01a064cd-b6c3-7c37-a83b-5722c5b86292" xlink:to="loc_innv_ContingentConsiderationSharesMilestoneOneMember_01a064cd-b6c3-7955-bf46-911a9cd4adf3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ContingentConsiderationSharesMilestoneThreeMember_01a064cd-b6c3-7e31-b621-0376a4b1d157" xlink:href="innv-20260930.xsd#innv_ContingentConsiderationSharesMilestoneThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_innv_ContingentConsiderationSharesMilestoneDomain_01a064cd-b6c3-7c37-a83b-5722c5b86292" xlink:to="loc_innv_ContingentConsiderationSharesMilestoneThreeMember_01a064cd-b6c3-7e31-b621-0376a4b1d157" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_BusinessCombinationContingentConsiderationShares_01a064cd-b6c3-7065-a5db-00dfcba5dc10" xlink:href="innv-20260930.xsd#innv_BusinessCombinationContingentConsiderationShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionContingentConsiderationLineItems_01a064cd-b6c3-7f89-a43e-c560f37305c0" xlink:to="loc_innv_BusinessCombinationContingentConsiderationShares_01a064cd-b6c3-7065-a5db-00dfcba5dc10" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_BusinessCombinationContingentConsiderationSharesVested_01a064cd-b6c3-758f-92d8-c045dbea7891" xlink:href="innv-20260930.xsd#innv_BusinessCombinationContingentConsiderationSharesVested"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionContingentConsiderationLineItems_01a064cd-b6c3-7f89-a43e-c560f37305c0" xlink:to="loc_innv_BusinessCombinationContingentConsiderationSharesVested_01a064cd-b6c3-758f-92d8-c045dbea7891" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ContingentConsiderationSharesVestingProvisionVolumeWeightedAveragePriceStockPriceTrigger_01a064cd-b6c3-75a5-b46a-4c5e8f9bcdb5" xlink:href="innv-20260930.xsd#innv_ContingentConsiderationSharesVestingProvisionVolumeWeightedAveragePriceStockPriceTrigger"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionContingentConsiderationLineItems_01a064cd-b6c3-7f89-a43e-c560f37305c0" xlink:to="loc_innv_ContingentConsiderationSharesVestingProvisionVolumeWeightedAveragePriceStockPriceTrigger_01a064cd-b6c3-75a5-b46a-4c5e8f9bcdb5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ContingentConsiderationSharesVestingProvisionVolumeWeightedAveragePriceThresholdTradingDays_01a064cd-b6c3-70a7-b0b2-a864168ca0c7" xlink:href="innv-20260930.xsd#innv_ContingentConsiderationSharesVestingProvisionVolumeWeightedAveragePriceThresholdTradingDays"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionContingentConsiderationLineItems_01a064cd-b6c3-7f89-a43e-c560f37305c0" xlink:to="loc_innv_ContingentConsiderationSharesVestingProvisionVolumeWeightedAveragePriceThresholdTradingDays_01a064cd-b6c3-70a7-b0b2-a864168ca0c7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ContingentConsiderationSharesVestingProvisionEffectivePeriodFollowingBusinessCombination_01a064cd-b6c3-7a24-9cd3-4239b7e5eac0" xlink:href="innv-20260930.xsd#innv_ContingentConsiderationSharesVestingProvisionEffectivePeriodFollowingBusinessCombination"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionContingentConsiderationLineItems_01a064cd-b6c3-7f89-a43e-c560f37305c0" xlink:to="loc_innv_ContingentConsiderationSharesVestingProvisionEffectivePeriodFollowingBusinessCombination_01a064cd-b6c3-7a24-9cd3-4239b7e5eac0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_BusinessCombinationContingentConsiderationSharesIssued_01a064cd-b6c3-7bb3-afda-1e34d86f5ab0" xlink:href="innv-20260930.xsd#innv_BusinessCombinationContingentConsiderationSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionContingentConsiderationLineItems_01a064cd-b6c3-7f89-a43e-c560f37305c0" xlink:to="loc_innv_BusinessCombinationContingentConsiderationSharesIssued_01a064cd-b6c3-7bb3-afda-1e34d86f5ab0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_BusinessCombinationContingentConsiderationLiabilityRevenueThreshold_01a064cd-b6c3-7c3f-aca6-e13326d4cd95" xlink:href="innv-20260930.xsd#innv_BusinessCombinationContingentConsiderationLiabilityRevenueThreshold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionContingentConsiderationLineItems_01a064cd-b6c3-7f89-a43e-c560f37305c0" xlink:to="loc_innv_BusinessCombinationContingentConsiderationLiabilityRevenueThreshold_01a064cd-b6c3-7c3f-aca6-e13326d4cd95" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_BusinessCombinationContingentConsiderationSharesForfeited_01a155e8-7e53-7029-aa86-b5435e5d3732" xlink:href="innv-20260930.xsd#innv_BusinessCombinationContingentConsiderationSharesForfeited"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionContingentConsiderationLineItems_01a064cd-b6c3-7f89-a43e-c560f37305c0" xlink:to="loc_innv_BusinessCombinationContingentConsiderationSharesForfeited_01a155e8-7e53-7029-aa86-b5435e5d3732" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_01a064cd-b6c3-7fa0-affb-7ff13a9bad57" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationContingentConsiderationLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionContingentConsiderationLineItems_01a064cd-b6c3-7f89-a43e-c560f37305c0" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_01a064cd-b6c3-7fa0-affb-7ff13a9bad57" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1_01a064cd-b6c3-71f3-974a-1f796e285e3a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionContingentConsiderationLineItems_01a064cd-b6c3-7f89-a43e-c560f37305c0" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1_01a064cd-b6c3-71f3-974a-1f796e285e3a" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/WarrantsScheduleofWarrantsDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#WarrantsScheduleofWarrantsDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/WarrantsScheduleofWarrantsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a064cd-b6c3-7621-9a38-18fbc0caa309" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightTable_01a064cd-b6c3-7708-b7e9-8dbf06ba3513" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a064cd-b6c3-7621-9a38-18fbc0caa309" xlink:to="loc_us-gaap_ClassOfWarrantOrRightTable_01a064cd-b6c3-7708-b7e9-8dbf06ba3513" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b6c3-76b0-90a7-3b546db8a1d2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ClassOfWarrantOrRightTable_01a064cd-b6c3-7708-b7e9-8dbf06ba3513" xlink:to="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b6c3-76b0-90a7-3b546db8a1d2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b6c3-76b0-90a7-3b546db8a1d2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b6c3-76b0-90a7-3b546db8a1d2" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b6c3-76b0-90a7-3b546db8a1d2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b6c3-7328-952b-70c924a539d1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b6c3-76b0-90a7-3b546db8a1d2" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b6c3-7328-952b-70c924a539d1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_PublicWarrantsMember_01a064cd-b6c3-7bec-9614-d811bd5278e4" xlink:href="innv-20260930.xsd#innv_PublicWarrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b6c3-7328-952b-70c924a539d1" xlink:to="loc_innv_PublicWarrantsMember_01a064cd-b6c3-7bec-9614-d811bd5278e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_PrivatePlacementWarrantsMember_01a064cd-b6c3-7415-810e-0f021d87e526" xlink:href="innv-20260930.xsd#innv_PrivatePlacementWarrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b6c3-7328-952b-70c924a539d1" xlink:to="loc_innv_PrivatePlacementWarrantsMember_01a064cd-b6c3-7415-810e-0f021d87e526" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_A2024WTIWarrantMember_01a064cd-b6c3-77fc-bdb3-84a4896d8946" xlink:href="innv-20260930.xsd#innv_A2024WTIWarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b6c3-7328-952b-70c924a539d1" xlink:to="loc_innv_A2024WTIWarrantMember_01a064cd-b6c3-77fc-bdb3-84a4896d8946" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_A2025WTIWarrantMember_01a064cd-b6c3-7ba4-b0c3-17b8e7b506b3" xlink:href="innv-20260930.xsd#innv_A2025WTIWarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b6c3-7328-952b-70c924a539d1" xlink:to="loc_innv_A2025WTIWarrantMember_01a064cd-b6c3-7ba4-b0c3-17b8e7b506b3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_SeriesAWarrantsMember_01a064cd-b6c3-71d0-b8a1-6804bfe915cd" xlink:href="innv-20260930.xsd#innv_SeriesAWarrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b6c3-7328-952b-70c924a539d1" xlink:to="loc_innv_SeriesAWarrantsMember_01a064cd-b6c3-71d0-b8a1-6804bfe915cd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ClassOfWarrantOrRightRollForward_01a064cd-b6c3-79a4-8994-725f2e27ba46" xlink:href="innv-20260930.xsd#innv_ClassOfWarrantOrRightRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a064cd-b6c3-7621-9a38-18fbc0caa309" xlink:to="loc_innv_ClassOfWarrantOrRightRollForward_01a064cd-b6c3-79a4-8994-725f2e27ba46" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightOutstanding_01a064cd-b6c3-7dd0-a04c-26075ba433bb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_innv_ClassOfWarrantOrRightRollForward_01a064cd-b6c3-79a4-8994-725f2e27ba46" xlink:to="loc_us-gaap_ClassOfWarrantOrRightOutstanding_01a064cd-b6c3-7dd0-a04c-26075ba433bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ClassOfWarrantOrRightExercised_01a064cd-b6c3-77f8-9037-1d948026b8a0" xlink:href="innv-20260930.xsd#innv_ClassOfWarrantOrRightExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_innv_ClassOfWarrantOrRightRollForward_01a064cd-b6c3-79a4-8994-725f2e27ba46" xlink:to="loc_innv_ClassOfWarrantOrRightExercised_01a064cd-b6c3-77f8-9037-1d948026b8a0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ClassOfWarrantOrRightIssued_01a064cd-b6c3-7bbc-b5cd-bc7dfda8e616" xlink:href="innv-20260930.xsd#innv_ClassOfWarrantOrRightIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_innv_ClassOfWarrantOrRightRollForward_01a064cd-b6c3-79a4-8994-725f2e27ba46" xlink:to="loc_innv_ClassOfWarrantOrRightIssued_01a064cd-b6c3-7bbc-b5cd-bc7dfda8e616" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightOutstanding_01a064cd-b6c3-7c17-9b8b-f7fc93381635" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightOutstanding"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/WarrantsNarrativeDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#WarrantsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/WarrantsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a064cd-b6c3-7d7d-a59f-fe32a6d8345e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightTable_01a064cd-b6c3-7ed1-95dd-b687a15f35bd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a064cd-b6c3-7d7d-a59f-fe32a6d8345e" xlink:to="loc_us-gaap_ClassOfWarrantOrRightTable_01a064cd-b6c3-7ed1-95dd-b687a15f35bd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b6c3-7bc0-a0db-9bdcae7fa625" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ClassOfWarrantOrRightTable_01a064cd-b6c3-7ed1-95dd-b687a15f35bd" xlink:to="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b6c3-7bc0-a0db-9bdcae7fa625" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b6c3-7bc0-a0db-9bdcae7fa625_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b6c3-7bc0-a0db-9bdcae7fa625" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b6c3-7bc0-a0db-9bdcae7fa625_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b6c3-7636-813e-5a1489e949c6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_01a064cd-b6c3-7bc0-a0db-9bdcae7fa625" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b6c3-7636-813e-5a1489e949c6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_PublicWarrantsMember_01a064cd-b6c3-708c-bdd4-7eb6bef9dc8f" xlink:href="innv-20260930.xsd#innv_PublicWarrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b6c3-7636-813e-5a1489e949c6" xlink:to="loc_innv_PublicWarrantsMember_01a064cd-b6c3-708c-bdd4-7eb6bef9dc8f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_PrivatePlacementWarrantsMember_01a064cd-b6c3-7b0b-813f-bf1a4fa92ee5" xlink:href="innv-20260930.xsd#innv_PrivatePlacementWarrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b6c3-7636-813e-5a1489e949c6" xlink:to="loc_innv_PrivatePlacementWarrantsMember_01a064cd-b6c3-7b0b-813f-bf1a4fa92ee5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_A2024WTIWarrantMember_01a064cd-b6c3-7267-ac91-24c029f7195f" xlink:href="innv-20260930.xsd#innv_A2024WTIWarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b6c3-7636-813e-5a1489e949c6" xlink:to="loc_innv_A2024WTIWarrantMember_01a064cd-b6c3-7267-ac91-24c029f7195f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_A2025WTIWarrantMember_01a064cd-b6c3-7455-9e2e-472d47c8d986" xlink:href="innv-20260930.xsd#innv_A2025WTIWarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b6c3-7636-813e-5a1489e949c6" xlink:to="loc_innv_A2025WTIWarrantMember_01a064cd-b6c3-7455-9e2e-472d47c8d986" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_SeriesAWarrantsMember_01a064cd-b6c3-7268-b70a-6f33bde09074" xlink:href="innv-20260930.xsd#innv_SeriesAWarrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_01a064cd-b6c3-7636-813e-5a1489e949c6" xlink:to="loc_innv_SeriesAWarrantsMember_01a064cd-b6c3-7268-b70a-6f33bde09074" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_01a064cd-b6c3-7702-a81f-9989806d6f57" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ClassOfWarrantOrRightTable_01a064cd-b6c3-7ed1-95dd-b687a15f35bd" xlink:to="loc_srt_RangeAxis_01a064cd-b6c3-7702-a81f-9989806d6f57" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_01a064cd-b6c3-7702-a81f-9989806d6f57_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_01a064cd-b6c3-7702-a81f-9989806d6f57" xlink:to="loc_srt_RangeMember_01a064cd-b6c3-7702-a81f-9989806d6f57_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_01a064cd-b6c3-7448-9a4c-fd128a4a6bf9" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_01a064cd-b6c3-7702-a81f-9989806d6f57" xlink:to="loc_srt_RangeMember_01a064cd-b6c3-7448-9a4c-fd128a4a6bf9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_01a064cd-b6c3-7d3a-af77-a01e87e20b95" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_01a064cd-b6c3-7448-9a4c-fd128a4a6bf9" xlink:to="loc_srt_MaximumMember_01a064cd-b6c3-7d3a-af77-a01e87e20b95" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_01a064cd-b6c3-7e4d-b784-154507f28e70" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ClassOfWarrantOrRightTable_01a064cd-b6c3-7ed1-95dd-b687a15f35bd" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_01a064cd-b6c3-7e4d-b784-154507f28e70" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_01a064cd-b6c3-7e4d-b784-154507f28e70_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_01a064cd-b6c3-7e4d-b784-154507f28e70" xlink:to="loc_us-gaap_EquityComponentDomain_01a064cd-b6c3-7e4d-b784-154507f28e70_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_01a064cd-b6c3-7f1d-9e02-433daac57b1c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_01a064cd-b6c3-7e4d-b784-154507f28e70" xlink:to="loc_us-gaap_EquityComponentDomain_01a064cd-b6c3-7f1d-9e02-433daac57b1c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_01a064cd-b6c3-70cc-a41d-f1157481fb9e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01a064cd-b6c3-7f1d-9e02-433daac57b1c" xlink:to="loc_us-gaap_CommonStockMember_01a064cd-b6c3-70cc-a41d-f1157481fb9e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_01a1a8b9-deee-76c7-9183-0cc09e005040" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ClassOfWarrantOrRightTable_01a064cd-b6c3-7ed1-95dd-b687a15f35bd" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_01a1a8b9-deee-76c7-9183-0cc09e005040" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_01a1a8b9-deee-76c7-9183-0cc09e005040_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_01a1a8b9-deee-76c7-9183-0cc09e005040" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_01a1a8b9-deee-76c7-9183-0cc09e005040_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_01a1a8b9-deee-7552-ba69-730f0417ad77" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_01a1a8b9-deee-76c7-9183-0cc09e005040" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_01a1a8b9-deee-7552-ba69-730f0417ad77" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_01a1a8b9-f52a-7c34-a573-65b0d231e40c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_01a1a8b9-deee-7552-ba69-730f0417ad77" xlink:to="loc_us-gaap_SubsequentEventMember_01a1a8b9-f52a-7c34-a573-65b0d231e40c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_01a064cd-b6c3-7236-b174-7b43d62972f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a064cd-b6c3-7d7d-a59f-fe32a6d8345e" xlink:to="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_01a064cd-b6c3-7236-b174-7b43d62972f2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WarrantsAndRightsOutstanding_01a064cd-b6c3-7330-9091-fd4bae4e853d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_WarrantsAndRightsOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a064cd-b6c3-7d7d-a59f-fe32a6d8345e" xlink:to="loc_us-gaap_WarrantsAndRightsOutstanding_01a064cd-b6c3-7330-9091-fd4bae4e853d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAdjustmentOfWarrants_01a064cd-b6c3-7958-80c2-11a7f7aa1d3b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAdjustmentOfWarrants"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a064cd-b6c3-7d7d-a59f-fe32a6d8345e" xlink:to="loc_us-gaap_FairValueAdjustmentOfWarrants_01a064cd-b6c3-7958-80c2-11a7f7aa1d3b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ClassOfWarrantOrRightAggregateCoverageAmount_01a064cd-b6c3-7894-9d80-a8df0a3ab7ba" xlink:href="innv-20260930.xsd#innv_ClassOfWarrantOrRightAggregateCoverageAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a064cd-b6c3-7d7d-a59f-fe32a6d8345e" xlink:to="loc_innv_ClassOfWarrantOrRightAggregateCoverageAmount_01a064cd-b6c3-7894-9d80-a8df0a3ab7ba" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ClassOfWarrantOrRightInitialExercisePriceOfWarrantsOrRights_01a064cd-b6c3-7147-b398-db9e591dff20" xlink:href="innv-20260930.xsd#innv_ClassOfWarrantOrRightInitialExercisePriceOfWarrantsOrRights"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a064cd-b6c3-7d7d-a59f-fe32a6d8345e" xlink:to="loc_innv_ClassOfWarrantOrRightInitialExercisePriceOfWarrantsOrRights_01a064cd-b6c3-7147-b398-db9e591dff20" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_SaleOfStockStockPriceDailyVolumeWeightedAveragePriceNumberOfConsecutiveTradingDays_01a064cd-b6c3-7be3-8819-cd6ca52d11f9" xlink:href="innv-20260930.xsd#innv_SaleOfStockStockPriceDailyVolumeWeightedAveragePriceNumberOfConsecutiveTradingDays"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a064cd-b6c3-7d7d-a59f-fe32a6d8345e" xlink:to="loc_innv_SaleOfStockStockPriceDailyVolumeWeightedAveragePriceNumberOfConsecutiveTradingDays_01a064cd-b6c3-7be3-8819-cd6ca52d11f9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ClassOfWarrantOrRightTermSinceCommonStockBeganTrading_01a064cd-b6c3-7f68-8628-0c001496086d" xlink:href="innv-20260930.xsd#innv_ClassOfWarrantOrRightTermSinceCommonStockBeganTrading"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a064cd-b6c3-7d7d-a59f-fe32a6d8345e" xlink:to="loc_innv_ClassOfWarrantOrRightTermSinceCommonStockBeganTrading_01a064cd-b6c3-7f68-8628-0c001496086d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_CommonStockVolumeWeightedAveragePrice_01a064cd-b6c3-7956-8131-bdcb49f94fcf" xlink:href="innv-20260930.xsd#innv_CommonStockVolumeWeightedAveragePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a064cd-b6c3-7d7d-a59f-fe32a6d8345e" xlink:to="loc_innv_CommonStockVolumeWeightedAveragePrice_01a064cd-b6c3-7956-8131-bdcb49f94fcf" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_01a064cd-b6c3-7949-9eb4-2e34209f88e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a064cd-b6c3-7d7d-a59f-fe32a6d8345e" xlink:to="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_01a064cd-b6c3-7949-9eb4-2e34209f88e3" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRightsAmount_01a064cd-b6c3-7a0a-9d8a-b4b3245d715a" xlink:href="innv-20260930.xsd#innv_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRightsAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a064cd-b6c3-7d7d-a59f-fe32a6d8345e" xlink:to="loc_innv_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRightsAmount_01a064cd-b6c3-7a0a-9d8a-b4b3245d715a" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ClassOfWarrantOrRightMinimumGrossCashProceedsElectToBecomeExercisable_01a1a8bb-401e-717d-9aec-c592b15228be" xlink:href="innv-20260930.xsd#innv_ClassOfWarrantOrRightMinimumGrossCashProceedsElectToBecomeExercisable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a064cd-b6c3-7d7d-a59f-fe32a6d8345e" xlink:to="loc_innv_ClassOfWarrantOrRightMinimumGrossCashProceedsElectToBecomeExercisable_01a1a8bb-401e-717d-9aec-c592b15228be" xlink:type="arc" order="10"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/StockholdersEquityDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#StockholdersEquityDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/StockholdersEquityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_01a064cd-b6c3-75d2-98c0-26aa73a22edd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_01a064cd-b6c3-75d2-98c0-26aa73a22edd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_01a064cd-b6c3-7307-a86e-eec39e1f7685" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_01a064cd-b6c3-75d2-98c0-26aa73a22edd" xlink:to="loc_us-gaap_StatementClassOfStockAxis_01a064cd-b6c3-7307-a86e-eec39e1f7685" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_01a064cd-b6c3-7307-a86e-eec39e1f7685_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_01a064cd-b6c3-7307-a86e-eec39e1f7685" xlink:to="loc_us-gaap_ClassOfStockDomain_01a064cd-b6c3-7307-a86e-eec39e1f7685_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_01a064cd-b6c3-76b9-a8e2-b90dc3284efb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_01a064cd-b6c3-7307-a86e-eec39e1f7685" xlink:to="loc_us-gaap_ClassOfStockDomain_01a064cd-b6c3-76b9-a8e2-b90dc3284efb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesBPreferredStockMember_01a064cd-b6c3-751c-84ad-3413a9662da1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeriesBPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_01a064cd-b6c3-76b9-a8e2-b90dc3284efb" xlink:to="loc_us-gaap_SeriesBPreferredStockMember_01a064cd-b6c3-751c-84ad-3413a9662da1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesCPreferredStockMember_01a064cd-b6c3-72cd-aa0d-6cb8b789a7b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeriesCPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_01a064cd-b6c3-76b9-a8e2-b90dc3284efb" xlink:to="loc_us-gaap_SeriesCPreferredStockMember_01a064cd-b6c3-72cd-aa0d-6cb8b789a7b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_01a064cd-b6c3-7a3f-b3de-4e4ec7e79f2c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_01a064cd-b6c3-75d2-98c0-26aa73a22edd" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_01a064cd-b6c3-7a3f-b3de-4e4ec7e79f2c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_01a064cd-b6c3-7a3f-b3de-4e4ec7e79f2c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_01a064cd-b6c3-7a3f-b3de-4e4ec7e79f2c" xlink:to="loc_us-gaap_EquityComponentDomain_01a064cd-b6c3-7a3f-b3de-4e4ec7e79f2c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_01a064cd-b6c3-7bde-a064-bb8972d3d5e5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_01a064cd-b6c3-7a3f-b3de-4e4ec7e79f2c" xlink:to="loc_us-gaap_EquityComponentDomain_01a064cd-b6c3-7bde-a064-bb8972d3d5e5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_01a064cd-b6c3-7d79-a2db-548eb40e3c10" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01a064cd-b6c3-7bde-a064-bb8972d3d5e5" xlink:to="loc_us-gaap_CommonStockMember_01a064cd-b6c3-7d79-a2db-548eb40e3c10" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockAxis_01a064cd-b6c3-7ac2-8df9-19d0fa449118" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_01a064cd-b6c3-75d2-98c0-26aa73a22edd" xlink:to="loc_us-gaap_SubsidiarySaleOfStockAxis_01a064cd-b6c3-7ac2-8df9-19d0fa449118" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_01a064cd-b6c3-7ac2-8df9-19d0fa449118_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_01a064cd-b6c3-7ac2-8df9-19d0fa449118" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_01a064cd-b6c3-7ac2-8df9-19d0fa449118_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_01a064cd-b6c3-750a-b40d-756f035740f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_01a064cd-b6c3-7ac2-8df9-19d0fa449118" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_01a064cd-b6c3-750a-b40d-756f035740f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_StandbyEquityPurchaseAgreementMember_01a064cd-b6c3-7098-a378-f4955dfdb187" xlink:href="innv-20260930.xsd#innv_StandbyEquityPurchaseAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain_01a064cd-b6c3-750a-b40d-756f035740f3" xlink:to="loc_innv_StandbyEquityPurchaseAgreementMember_01a064cd-b6c3-7098-a378-f4955dfdb187" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrivatePlacementMember_01a064cd-b6c3-752d-8e4e-8116855e994b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PrivatePlacementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain_01a064cd-b6c3-750a-b40d-756f035740f3" xlink:to="loc_us-gaap_PrivatePlacementMember_01a064cd-b6c3-752d-8e4e-8116855e994b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_AtTheMarketOfferingMember_01a1a8b2-919c-7bd1-863f-4233f7d6c2e1" xlink:href="innv-20260930.xsd#innv_AtTheMarketOfferingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain_01a064cd-b6c3-750a-b40d-756f035740f3" xlink:to="loc_innv_AtTheMarketOfferingMember_01a1a8b2-919c-7bd1-863f-4233f7d6c2e1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_01a064cd-b6c3-74a2-8c7f-ce6fe298b456" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_01a064cd-b6c3-75d2-98c0-26aa73a22edd" xlink:to="loc_us-gaap_DebtInstrumentAxis_01a064cd-b6c3-74a2-8c7f-ce6fe298b456" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b6c3-74a2-8c7f-ce6fe298b456_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a064cd-b6c3-74a2-8c7f-ce6fe298b456" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b6c3-74a2-8c7f-ce6fe298b456_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b6c3-76e2-96e7-65ec87a617f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a064cd-b6c3-74a2-8c7f-ce6fe298b456" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b6c3-76e2-96e7-65ec87a617f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_RelatedPartyNoteThreeMember_01a064cd-b6c3-737a-99ee-c9348862319c" xlink:href="innv-20260930.xsd#innv_RelatedPartyNoteThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a064cd-b6c3-76e2-96e7-65ec87a617f2" xlink:to="loc_innv_RelatedPartyNoteThreeMember_01a064cd-b6c3-737a-99ee-c9348862319c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b6c3-7d95-8329-96868792a10a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_01a064cd-b6c3-75d2-98c0-26aa73a22edd" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b6c3-7d95-8329-96868792a10a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b6c3-7d95-8329-96868792a10a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b6c3-7d95-8329-96868792a10a" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b6c3-7d95-8329-96868792a10a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b6c3-7bdd-88e7-134328e55684" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a064cd-b6c3-7d95-8329-96868792a10a" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b6c3-7bdd-88e7-134328e55684" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableOtherPayablesMember_01a064cd-b6c3-775c-8085-1c1d74bec3a2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesPayableOtherPayablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_01a064cd-b6c3-7bdd-88e7-134328e55684" xlink:to="loc_us-gaap_NotesPayableOtherPayablesMember_01a064cd-b6c3-775c-8085-1c1d74bec3a2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_01a1a8af-4b68-7065-8e98-5fa8d96a603b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_01a064cd-b6c3-75d2-98c0-26aa73a22edd" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_01a1a8af-4b68-7065-8e98-5fa8d96a603b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_01a1a8af-4b68-7065-8e98-5fa8d96a603b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_01a1a8af-4b68-7065-8e98-5fa8d96a603b" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_01a1a8af-4b68-7065-8e98-5fa8d96a603b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_01a1a8af-4b68-7ba4-9f1c-7686083b56b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_01a1a8af-4b68-7065-8e98-5fa8d96a603b" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_01a1a8af-4b68-7ba4-9f1c-7686083b56b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_01a1a8af-648d-7332-9e02-636c5014eb97" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_01a1a8af-4b68-7ba4-9f1c-7686083b56b4" xlink:to="loc_us-gaap_SubsequentEventMember_01a1a8af-648d-7332-9e02-636c5014eb97" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_01a064cd-b6c3-7df9-a54a-d0b48095f9d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_01a064cd-b6c3-7df9-a54a-d0b48095f9d8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_01a064cd-b6c3-7606-a3c7-2f13d3e9143f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_01a064cd-b6c3-7606-a3c7-2f13d3e9143f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendRatePercentage_01a064cd-b6c3-7cbc-a72e-3ba99113a339" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockDividendRatePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_us-gaap_PreferredStockDividendRatePercentage_01a064cd-b6c3-7cbc-a72e-3ba99113a339" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockDividendsShares_01a064cd-b6c3-7dd6-a145-f651e9e61e5c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockDividendsShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_us-gaap_StockDividendsShares_01a064cd-b6c3-7dd6-a145-f651e9e61e5c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TemporaryEquitySharesConversionOfConvertibleSecurities_01a064cd-b6c3-72f6-a1c0-f8b8c20fd976" xlink:href="innv-20260930.xsd#innv_TemporaryEquitySharesConversionOfConvertibleSecurities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_innv_TemporaryEquitySharesConversionOfConvertibleSecurities_01a064cd-b6c3-72f6-a1c0-f8b8c20fd976" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_01a064cd-b6c3-77eb-adee-f3844cdb6114" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_01a064cd-b6c3-77eb-adee-f3844cdb6114" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesIssued_01a064cd-b6c3-70d9-b2fe-e6a89d9ef976" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_us-gaap_PreferredStockSharesIssued_01a064cd-b6c3-70d9-b2fe-e6a89d9ef976" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TemporaryEquityStockIssuedDuringPeriodSharesNewIssuesAndConversionOfDebt_01a064cd-b6c3-7802-94c4-303c8c1354f0" xlink:href="innv-20260930.xsd#innv_TemporaryEquityStockIssuedDuringPeriodSharesNewIssuesAndConversionOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_innv_TemporaryEquityStockIssuedDuringPeriodSharesNewIssuesAndConversionOfDebt_01a064cd-b6c3-7802-94c4-303c8c1354f0" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_EquityIssuanceLiabilityCurrent_01a064cd-b6c3-704b-9718-20f2cc9a82ad" xlink:href="innv-20260930.xsd#innv_EquityIssuanceLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_innv_EquityIssuanceLiabilityCurrent_01a064cd-b6c3-704b-9718-20f2cc9a82ad" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExtinguishmentOfDebtAmount_01a064cd-b6c3-7f15-97ca-9841b99fc0f1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ExtinguishmentOfDebtAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_us-gaap_ExtinguishmentOfDebtAmount_01a064cd-b6c3-7f15-97ca-9841b99fc0f1" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_01a064cd-b6c3-7713-ae10-8e073dd86a81" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_01a064cd-b6c3-7713-ae10-8e073dd86a81" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_SaleOfStockMaximumRightToSell_01a064cd-b6c3-7bf3-a67d-815bd14c3d60" xlink:href="innv-20260930.xsd#innv_SaleOfStockMaximumRightToSell"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_innv_SaleOfStockMaximumRightToSell_01a064cd-b6c3-7bf3-a67d-815bd14c3d60" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_SaleOfStockTermToSell_01a1a8a7-b0d7-7e3d-88e8-f2fbb74e55bc" xlink:href="innv-20260930.xsd#innv_SaleOfStockTermToSell"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_innv_SaleOfStockTermToSell_01a1a8a7-b0d7-7e3d-88e8-f2fbb74e55bc" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_01a064cd-b6c3-7ff6-af00-85fe00b7b7ce" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_01a064cd-b6c3-7ff6-af00-85fe00b7b7ce" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockConsiderationReceivedOnTransaction_01a064cd-b6c3-7e4c-b5e7-8bcee9ff126b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SaleOfStockConsiderationReceivedOnTransaction"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_us-gaap_SaleOfStockConsiderationReceivedOnTransaction_01a064cd-b6c3-7e4c-b5e7-8bcee9ff126b" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_SaleOfStockRemainingAuthorizedAmount_01a064cd-b6c3-765f-a3f3-8dbae57fe50a" xlink:href="innv-20260930.xsd#innv_SaleOfStockRemainingAuthorizedAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_innv_SaleOfStockRemainingAuthorizedAmount_01a064cd-b6c3-765f-a3f3-8dbae57fe50a" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_SaleOfStockCommissionPercentageOfGrossSalesPriceFirstMilestone_01a1a8b4-7cb0-79ac-99fa-8a0bce4b1eb8" xlink:href="innv-20260930.xsd#innv_SaleOfStockCommissionPercentageOfGrossSalesPriceFirstMilestone"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_innv_SaleOfStockCommissionPercentageOfGrossSalesPriceFirstMilestone_01a1a8b4-7cb0-79ac-99fa-8a0bce4b1eb8" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_SaleOfStockCommissionGrossSalesPriceFirstMilestone_01a1a8b6-b79a-7f84-96cd-bec8547b4303" xlink:href="innv-20260930.xsd#innv_SaleOfStockCommissionGrossSalesPriceFirstMilestone"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_innv_SaleOfStockCommissionGrossSalesPriceFirstMilestone_01a1a8b6-b79a-7f84-96cd-bec8547b4303" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_SaleOfStockCommissionPercentageOfGrossSalesPriceSecondMilestone_01a1a8b6-35b6-7ba7-b254-fdebfc6411d8" xlink:href="innv-20260930.xsd#innv_SaleOfStockCommissionPercentageOfGrossSalesPriceSecondMilestone"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_innv_SaleOfStockCommissionPercentageOfGrossSalesPriceSecondMilestone_01a1a8b6-35b6-7ba7-b254-fdebfc6411d8" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_SaleOfStockCommissionGrossSalesPriceSecondMilestone_01a1a8b6-e781-795b-8749-47e452a7aa42" xlink:href="innv-20260930.xsd#innv_SaleOfStockCommissionGrossSalesPriceSecondMilestone"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_innv_SaleOfStockCommissionGrossSalesPriceSecondMilestone_01a1a8b6-e781-795b-8749-47e452a7aa42" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_SaleOfStockCommissionsPaid_01a1a8b1-b0d7-73ce-ad4d-9d318f0726c4" xlink:href="innv-20260930.xsd#innv_SaleOfStockCommissionsPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_innv_SaleOfStockCommissionsPaid_01a1a8b1-b0d7-73ce-ad4d-9d318f0726c4" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_NumberOfInstitutionalInvestors_01a064cd-b6c3-7439-9de5-da5ed0dd78f0" xlink:href="innv-20260930.xsd#innv_NumberOfInstitutionalInvestors"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a064cd-b6c3-7495-9445-1145012ebf9b" xlink:to="loc_innv_NumberOfInstitutionalInvestors_01a064cd-b6c3-7439-9de5-da5ed0dd78f0" xlink:type="arc" order="21"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/StockbasedCompensationDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#StockbasedCompensationDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/StockbasedCompensationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a064cd-b6c3-7e5f-8975-8a88fd635a83" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_01a064cd-b6c3-79c1-b586-b26e2eafcf4d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a064cd-b6c3-7e5f-8975-8a88fd635a83" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_01a064cd-b6c3-79c1-b586-b26e2eafcf4d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_01a064cd-b6c3-7af7-b4bc-124d87ef55b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_01a064cd-b6c3-79c1-b586-b26e2eafcf4d" xlink:to="loc_us-gaap_AwardTypeAxis_01a064cd-b6c3-7af7-b4bc-124d87ef55b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_01a064cd-b6c3-7af7-b4bc-124d87ef55b4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_01a064cd-b6c3-7af7-b4bc-124d87ef55b4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_01a064cd-b6c3-7af7-b4bc-124d87ef55b4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_01a064cd-b6c3-7593-bfb6-6ca6022878f9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_01a064cd-b6c3-7af7-b4bc-124d87ef55b4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_01a064cd-b6c3-7593-bfb6-6ca6022878f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_01a064cd-b6c3-70b2-b1dd-2c8c1c1b353c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_01a064cd-b6c3-7593-bfb6-6ca6022878f9" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_01a064cd-b6c3-70b2-b1dd-2c8c1c1b353c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_01a064cd-b6c3-748e-a0d1-014b3748b486" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_01a064cd-b6c3-7593-bfb6-6ca6022878f9" xlink:to="loc_us-gaap_EmployeeStockOptionMember_01a064cd-b6c3-748e-a0d1-014b3748b486" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_CashSettledStockAppreciationRightsSARsMember_01a064cd-b6c3-75cf-b480-02131cc552bc" xlink:href="innv-20260930.xsd#innv_CashSettledStockAppreciationRightsSARsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_01a064cd-b6c3-7593-bfb6-6ca6022878f9" xlink:to="loc_innv_CashSettledStockAppreciationRightsSARsMember_01a064cd-b6c3-75cf-b480-02131cc552bc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockAppreciationRightsSARSMember_01a064cd-b6c3-78f5-b194-b8480fd5ae65" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockAppreciationRightsSARSMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_01a064cd-b6c3-7593-bfb6-6ca6022878f9" xlink:to="loc_us-gaap_StockAppreciationRightsSARSMember_01a064cd-b6c3-78f5-b194-b8480fd5ae65" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_01a064cd-b6c3-7b8f-857b-452ba9c25516" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_01a064cd-b6c3-79c1-b586-b26e2eafcf4d" xlink:to="loc_us-gaap_PlanNameAxis_01a064cd-b6c3-7b8f-857b-452ba9c25516" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_01a064cd-b6c3-7b8f-857b-452ba9c25516_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_01a064cd-b6c3-7b8f-857b-452ba9c25516" xlink:to="loc_us-gaap_PlanNameDomain_01a064cd-b6c3-7b8f-857b-452ba9c25516_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_01a064cd-b6c3-7288-a6f6-c201845bf9db" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_01a064cd-b6c3-7b8f-857b-452ba9c25516" xlink:to="loc_us-gaap_PlanNameDomain_01a064cd-b6c3-7288-a6f6-c201845bf9db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_SubsidiaryEquityPlanMember_01a064cd-b6c3-7528-a5e5-06eaccbfff30" xlink:href="innv-20260930.xsd#innv_SubsidiaryEquityPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_01a064cd-b6c3-7288-a6f6-c201845bf9db" xlink:to="loc_innv_SubsidiaryEquityPlanMember_01a064cd-b6c3-7528-a5e5-06eaccbfff30" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_01a064cd-b6c3-7fcd-967d-a2171515c7ff" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_01a064cd-b6c3-79c1-b586-b26e2eafcf4d" xlink:to="loc_dei_LegalEntityAxis_01a064cd-b6c3-7fcd-967d-a2171515c7ff" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_01a064cd-b6c3-7fcd-967d-a2171515c7ff_default" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_01a064cd-b6c3-7fcd-967d-a2171515c7ff" xlink:to="loc_dei_EntityDomain_01a064cd-b6c3-7fcd-967d-a2171515c7ff_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_01a064cd-b6c3-713a-8436-85830b7c9352" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_01a064cd-b6c3-7fcd-967d-a2171515c7ff" xlink:to="loc_dei_EntityDomain_01a064cd-b6c3-713a-8436-85830b7c9352" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_AccelsiusHoldingsLLCMember_01a064cd-b6c3-721a-af74-cacfd75dbcd3" xlink:href="innv-20260930.xsd#innv_AccelsiusHoldingsLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_01a064cd-b6c3-713a-8436-85830b7c9352" xlink:to="loc_innv_AccelsiusHoldingsLLCMember_01a064cd-b6c3-721a-af74-cacfd75dbcd3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_01a1a8a0-150f-7f3a-b7bc-661165fbc3c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_01a064cd-b6c3-79c1-b586-b26e2eafcf4d" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_01a1a8a0-150f-7f3a-b7bc-661165fbc3c7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_01a1a8a0-150f-7f3a-b7bc-661165fbc3c7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_01a1a8a0-150f-7f3a-b7bc-661165fbc3c7" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_01a1a8a0-150f-7f3a-b7bc-661165fbc3c7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_01a1a8a0-150f-7bb4-a1e3-e7c93afa5b37" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_01a1a8a0-150f-7f3a-b7bc-661165fbc3c7" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_01a1a8a0-150f-7bb4-a1e3-e7c93afa5b37" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_01a1a8a0-2fbf-76ba-91ed-5a62ab78c5d6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_01a1a8a0-150f-7bb4-a1e3-e7c93afa5b37" xlink:to="loc_us-gaap_SubsequentEventMember_01a1a8a0-2fbf-76ba-91ed-5a62ab78c5d6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_01a064cd-b6c3-7435-832e-8dcbad3e0c3f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a064cd-b6c3-7e5f-8975-8a88fd635a83" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_01a064cd-b6c3-7435-832e-8dcbad3e0c3f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ShareBasedCompensationArrangementByShareBasedPaymentAwardGrantedInPeriodFairValue_01a064cd-b6c3-793d-9a5e-cd21f888e261" xlink:href="innv-20260930.xsd#innv_ShareBasedCompensationArrangementByShareBasedPaymentAwardGrantedInPeriodFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a064cd-b6c3-7e5f-8975-8a88fd635a83" xlink:to="loc_innv_ShareBasedCompensationArrangementByShareBasedPaymentAwardGrantedInPeriodFairValue_01a064cd-b6c3-793d-9a5e-cd21f888e261" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_01a064cd-b6c3-79ac-a6fd-cf4784841486" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a064cd-b6c3-7e5f-8975-8a88fd635a83" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_01a064cd-b6c3-79ac-a6fd-cf4784841486" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_01a064cd-b6c3-75f1-b0d3-0e0a012afb3b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a064cd-b6c3-7e5f-8975-8a88fd635a83" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_01a064cd-b6c3-75f1-b0d3-0e0a012afb3b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_01a064cd-b6c3-77e8-9ee4-4faa07055052" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a064cd-b6c3-7e5f-8975-8a88fd635a83" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_01a064cd-b6c3-77e8-9ee4-4faa07055052" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_01a064cd-b6c3-7559-a828-d6383e43ac18" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a064cd-b6c3-7e5f-8975-8a88fd635a83" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_01a064cd-b6c3-7559-a828-d6383e43ac18" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_01a1a8a3-8794-7571-a7c1-63b67b3fa1c0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a064cd-b6c3-7e5f-8975-8a88fd635a83" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_01a1a8a3-8794-7571-a7c1-63b67b3fa1c0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_01a064cd-b6c3-795c-88c8-40fd34f6b04a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a064cd-b6c3-7e5f-8975-8a88fd635a83" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_01a064cd-b6c3-795c-88c8-40fd34f6b04a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_01a064cd-b6c3-7453-ba05-3e2673d1ec79" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a064cd-b6c3-7e5f-8975-8a88fd635a83" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_01a064cd-b6c3-7453-ba05-3e2673d1ec79" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_01a064cd-b6c3-723d-a03c-c4a1d045b6c2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a064cd-b6c3-7e5f-8975-8a88fd635a83" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_01a064cd-b6c3-723d-a03c-c4a1d045b6c2" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_01a064cd-b6c3-7d95-ab41-ac787db0515f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a064cd-b6c3-7e5f-8975-8a88fd635a83" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_01a064cd-b6c3-7d95-ab41-ac787db0515f" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ShareBasedCompensationArrangementByShareBasedPaymentAwardBaseStockPriceForAwards_01a064cd-b6c3-7618-99b3-d7f436f3447d" xlink:href="innv-20260930.xsd#innv_ShareBasedCompensationArrangementByShareBasedPaymentAwardBaseStockPriceForAwards"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a064cd-b6c3-7e5f-8975-8a88fd635a83" xlink:to="loc_innv_ShareBasedCompensationArrangementByShareBasedPaymentAwardBaseStockPriceForAwards_01a064cd-b6c3-7618-99b3-d7f436f3447d" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_01a064cd-b6c3-7dd0-95ae-f136acdb7125" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a064cd-b6c3-7e5f-8975-8a88fd635a83" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_01a064cd-b6c3-7dd0-95ae-f136acdb7125" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_01a064cd-b6c3-7394-a40d-b03282c182d4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a064cd-b6c3-7e5f-8975-8a88fd635a83" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_01a064cd-b6c3-7394-a40d-b03282c182d4" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_01a064cd-b6c3-7994-9ac5-f1a0b878ea6b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a064cd-b6c3-7e5f-8975-8a88fd635a83" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_01a064cd-b6c3-7994-9ac5-f1a0b878ea6b" xlink:type="arc" order="14"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/NetLossPerShareAntidilutiveSecuritiesDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#NetLossPerShareAntidilutiveSecuritiesDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/NetLossPerShareAntidilutiveSecuritiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_01a064cd-b6c3-774c-90b3-9053121632b6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_01a064cd-b6c3-7db7-a61f-d3a7216f4c2c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_01a064cd-b6c3-774c-90b3-9053121632b6" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_01a064cd-b6c3-7db7-a61f-d3a7216f4c2c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_01a064cd-b6c3-7479-98d7-411f447cba9e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_01a064cd-b6c3-7db7-a61f-d3a7216f4c2c" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_01a064cd-b6c3-7479-98d7-411f447cba9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a064cd-b6c3-7479-98d7-411f447cba9e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_01a064cd-b6c3-7479-98d7-411f447cba9e" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a064cd-b6c3-7479-98d7-411f447cba9e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a064cd-b6c3-7390-9683-2a63f339962a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_01a064cd-b6c3-7479-98d7-411f447cba9e" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a064cd-b6c3-7390-9683-2a63f339962a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_PublicWarrantsMember_01a064cd-b6c3-766a-9f8d-fd694a0a092a" xlink:href="innv-20260930.xsd#innv_PublicWarrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a064cd-b6c3-7390-9683-2a63f339962a" xlink:to="loc_innv_PublicWarrantsMember_01a064cd-b6c3-766a-9f8d-fd694a0a092a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_PrivatePlacementWarrantsMember_01a064cd-b6c3-7ab7-81b6-f3f821efab86" xlink:href="innv-20260930.xsd#innv_PrivatePlacementWarrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a064cd-b6c3-7390-9683-2a63f339962a" xlink:to="loc_innv_PrivatePlacementWarrantsMember_01a064cd-b6c3-7ab7-81b6-f3f821efab86" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_A2024WTIWarrantMember_01a064cd-b6c3-7bf7-8696-94ff5351d26d" xlink:href="innv-20260930.xsd#innv_A2024WTIWarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a064cd-b6c3-7390-9683-2a63f339962a" xlink:to="loc_innv_A2024WTIWarrantMember_01a064cd-b6c3-7bf7-8696-94ff5351d26d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtSecuritiesMember_01a064cd-b6c3-743a-81ec-09e0c6e9690b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConvertibleDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a064cd-b6c3-7390-9683-2a63f339962a" xlink:to="loc_us-gaap_ConvertibleDebtSecuritiesMember_01a064cd-b6c3-743a-81ec-09e0c6e9690b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_A2025WTIWarrantMember_01a064cd-b6c3-709f-bd2c-58508b1d7612" xlink:href="innv-20260930.xsd#innv_A2025WTIWarrantMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a064cd-b6c3-7390-9683-2a63f339962a" xlink:to="loc_innv_A2025WTIWarrantMember_01a064cd-b6c3-709f-bd2c-58508b1d7612" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_SeriesAWarrantsMember_01a064cd-b6c3-7434-a6f1-afca3424c938" xlink:href="innv-20260930.xsd#innv_SeriesAWarrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a064cd-b6c3-7390-9683-2a63f339962a" xlink:to="loc_innv_SeriesAWarrantsMember_01a064cd-b6c3-7434-a6f1-afca3424c938" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesBPreferredStockMember_01a064cd-b6c3-70d4-9450-962afd513de3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeriesBPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a064cd-b6c3-7390-9683-2a63f339962a" xlink:to="loc_us-gaap_SeriesBPreferredStockMember_01a064cd-b6c3-70d4-9450-962afd513de3" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeriesCPreferredStockMember_01a064cd-b6c3-7a5b-9eb1-167f75704666" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeriesCPreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a064cd-b6c3-7390-9683-2a63f339962a" xlink:to="loc_us-gaap_SeriesCPreferredStockMember_01a064cd-b6c3-7a5b-9eb1-167f75704666" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_01a064cd-b6c3-70b6-9f0d-ea0b0e352d51" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a064cd-b6c3-7390-9683-2a63f339962a" xlink:to="loc_us-gaap_EmployeeStockOptionMember_01a064cd-b6c3-70b6-9f0d-ea0b0e352d51" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_01a064cd-b6c3-7d4b-b3ac-6315f60611c6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a064cd-b6c3-7390-9683-2a63f339962a" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_01a064cd-b6c3-7d4b-b3ac-6315f60611c6" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockAppreciationRightsSARSMember_01a064cd-b6c3-7717-8807-7dac79a0388e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockAppreciationRightsSARSMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a064cd-b6c3-7390-9683-2a63f339962a" xlink:to="loc_us-gaap_StockAppreciationRightsSARSMember_01a064cd-b6c3-7717-8807-7dac79a0388e" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_01a064cd-b6c3-79f6-99eb-b5c52fa23771" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_01a064cd-b6c3-774c-90b3-9053121632b6" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_01a064cd-b6c3-79f6-99eb-b5c52fa23771" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_01a064cd-b6c3-748b-9dee-33f397d340ac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_01a064cd-b6c3-774c-90b3-9053121632b6" xlink:to="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_01a064cd-b6c3-748b-9dee-33f397d340ac" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/RelatedPartyTransactionsDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#RelatedPartyTransactionsDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/RelatedPartyTransactionsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_01a064cd-b6c3-79bf-95a5-d3372922f33e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_01a064cd-b6c3-7da5-aaf6-8fc1b83faa8e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_01a064cd-b6c3-79bf-95a5-d3372922f33e" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_01a064cd-b6c3-7da5-aaf6-8fc1b83faa8e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_01a064cd-b6c3-75b3-b292-c9ee9f8c715c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_01a064cd-b6c3-7da5-aaf6-8fc1b83faa8e" xlink:to="loc_srt_RangeAxis_01a064cd-b6c3-75b3-b292-c9ee9f8c715c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_01a064cd-b6c3-75b3-b292-c9ee9f8c715c_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_01a064cd-b6c3-75b3-b292-c9ee9f8c715c" xlink:to="loc_srt_RangeMember_01a064cd-b6c3-75b3-b292-c9ee9f8c715c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_01a064cd-b6c3-703a-880c-b5dc8bad02fa" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_01a064cd-b6c3-75b3-b292-c9ee9f8c715c" xlink:to="loc_srt_RangeMember_01a064cd-b6c3-703a-880c-b5dc8bad02fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_01a064cd-b6c3-738a-b03a-2b41684bfdd7" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_01a064cd-b6c3-703a-880c-b5dc8bad02fa" xlink:to="loc_srt_MinimumMember_01a064cd-b6c3-738a-b03a-2b41684bfdd7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_01a064cd-b6c3-7a82-a5aa-724dc8d3e6d2" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_01a064cd-b6c3-703a-880c-b5dc8bad02fa" xlink:to="loc_srt_MaximumMember_01a064cd-b6c3-7a82-a5aa-724dc8d3e6d2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_01a064cd-b6c3-7980-abbe-992bc29133b0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_01a064cd-b6c3-7da5-aaf6-8fc1b83faa8e" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_01a064cd-b6c3-7980-abbe-992bc29133b0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_01a064cd-b6c3-7980-abbe-992bc29133b0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_01a064cd-b6c3-7980-abbe-992bc29133b0" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_01a064cd-b6c3-7980-abbe-992bc29133b0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_01a064cd-b6c3-7547-a587-e2e3d31a24fc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_01a064cd-b6c3-7980-abbe-992bc29133b0" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_01a064cd-b6c3-7547-a587-e2e3d31a24fc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TransactionsWithESGFundMember_01a064cd-b6c3-7ea3-9995-ef13b699c1b0" xlink:href="innv-20260930.xsd#innv_TransactionsWithESGFundMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_01a064cd-b6c3-7547-a587-e2e3d31a24fc" xlink:to="loc_innv_TransactionsWithESGFundMember_01a064cd-b6c3-7ea3-9995-ef13b699c1b0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TransactionsWithAeroFlexxMember_01a064cd-b6c3-7784-b9df-030367ed7ea2" xlink:href="innv-20260930.xsd#innv_TransactionsWithAeroFlexxMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_01a064cd-b6c3-7547-a587-e2e3d31a24fc" xlink:to="loc_innv_TransactionsWithAeroFlexxMember_01a064cd-b6c3-7784-b9df-030367ed7ea2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TransactionsWithVital1Member_01a1a892-2e22-77b9-91cf-0bec08a5d1ec" xlink:href="innv-20260930.xsd#innv_TransactionsWithVital1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_01a064cd-b6c3-7547-a587-e2e3d31a24fc" xlink:to="loc_innv_TransactionsWithVital1Member_01a1a892-2e22-77b9-91cf-0bec08a5d1ec" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a064cd-b6c3-7030-aaae-e48b514ab17f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_01a064cd-b6c3-7da5-aaf6-8fc1b83faa8e" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a064cd-b6c3-7030-aaae-e48b514ab17f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a064cd-b6c3-7030-aaae-e48b514ab17f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a064cd-b6c3-7030-aaae-e48b514ab17f" xlink:to="loc_us-gaap_RelatedPartyDomain_01a064cd-b6c3-7030-aaae-e48b514ab17f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a064cd-b6c3-7bf2-8264-cd645ee671aa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a064cd-b6c3-7030-aaae-e48b514ab17f" xlink:to="loc_us-gaap_RelatedPartyDomain_01a064cd-b6c3-7bf2-8264-cd645ee671aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_01a064cd-b6c3-75c4-a260-10b453eefeb7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_01a064cd-b6c3-7bf2-8264-cd645ee671aa" xlink:to="loc_us-gaap_RelatedPartyMember_01a064cd-b6c3-75c4-a260-10b453eefeb7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_01a064cd-b6c3-7111-917e-1647fcde3a30" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_01a064cd-b6c3-7da5-aaf6-8fc1b83faa8e" xlink:to="loc_srt_ProductOrServiceAxis_01a064cd-b6c3-7111-917e-1647fcde3a30" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_01a064cd-b6c3-7111-917e-1647fcde3a30_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_01a064cd-b6c3-7111-917e-1647fcde3a30" xlink:to="loc_srt_ProductsAndServicesDomain_01a064cd-b6c3-7111-917e-1647fcde3a30_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_01a064cd-b6c3-7d9a-b499-4ef100ba16ac" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_01a064cd-b6c3-7111-917e-1647fcde3a30" xlink:to="loc_srt_ProductsAndServicesDomain_01a064cd-b6c3-7d9a-b499-4ef100ba16ac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ManagementFeesMember_01a064cd-b6c3-7f68-b5fe-9f607f221357" xlink:href="innv-20260930.xsd#innv_ManagementFeesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_01a064cd-b6c3-7d9a-b499-4ef100ba16ac" xlink:to="loc_innv_ManagementFeesMember_01a064cd-b6c3-7f68-b5fe-9f607f221357" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_01a1a893-73c9-791a-ba73-85767d6f1e81" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_01a064cd-b6c3-7da5-aaf6-8fc1b83faa8e" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_01a1a893-73c9-791a-ba73-85767d6f1e81" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_01a1a893-73c9-791a-ba73-85767d6f1e81_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_01a1a893-73c9-791a-ba73-85767d6f1e81" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_01a1a893-73c9-791a-ba73-85767d6f1e81_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_01a1a893-73c9-71cd-9b30-6021647102d1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_01a1a893-73c9-791a-ba73-85767d6f1e81" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_01a1a893-73c9-71cd-9b30-6021647102d1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_01a1a893-8aa9-7a7f-aed7-dff71ad66937" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_01a1a893-73c9-71cd-9b30-6021647102d1" xlink:to="loc_us-gaap_SubsequentEventMember_01a1a893-8aa9-7a7f-aed7-dff71ad66937" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_01a1a894-806a-7a08-96b7-572057da8e60" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_01a064cd-b6c3-7da5-aaf6-8fc1b83faa8e" xlink:to="loc_us-gaap_DebtInstrumentAxis_01a1a894-806a-7a08-96b7-572057da8e60" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a1a894-806a-7a08-96b7-572057da8e60_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a1a894-806a-7a08-96b7-572057da8e60" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a1a894-806a-7a08-96b7-572057da8e60_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a1a894-806a-71de-84c1-46a140f0ab22" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a1a894-806a-7a08-96b7-572057da8e60" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a1a894-806a-71de-84c1-46a140f0ab22" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_SecuredPromissoryNoteMember_01a1a894-b5ee-7982-89c2-14dcd8739c01" xlink:href="innv-20260930.xsd#innv_SecuredPromissoryNoteMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a1a894-806a-71de-84c1-46a140f0ab22" xlink:to="loc_innv_SecuredPromissoryNoteMember_01a1a894-b5ee-7982-89c2-14dcd8739c01" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_01a1a894-d110-714b-9b04-c2ad3cf3d11d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_01a064cd-b6c3-7da5-aaf6-8fc1b83faa8e" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_01a1a894-d110-714b-9b04-c2ad3cf3d11d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a1a894-d110-714b-9b04-c2ad3cf3d11d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a1a894-d110-714b-9b04-c2ad3cf3d11d" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a1a894-d110-714b-9b04-c2ad3cf3d11d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a1a894-d110-75b7-9c25-f256c56acacc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a1a894-d110-714b-9b04-c2ad3cf3d11d" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a1a894-d110-75b7-9c25-f256c56acacc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_01a1a895-20ff-7b0f-ab64-be88cd758eb7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_01a1a894-d110-75b7-9c25-f256c56acacc" xlink:to="loc_us-gaap_SecuredDebtMember_01a1a895-20ff-7b0f-ab64-be88cd758eb7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ManagementAndServiceFeesBaseRate_01a064cd-b6c3-79b2-a897-094c9934427a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ManagementAndServiceFeesBaseRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_01a064cd-b6c3-79bf-95a5-d3372922f33e" xlink:to="loc_us-gaap_ManagementAndServiceFeesBaseRate_01a064cd-b6c3-79b2-a897-094c9934427a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_01a064cd-b6c3-72f1-b192-6cfa3f50b8f7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_01a064cd-b6c3-79bf-95a5-d3372922f33e" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_01a064cd-b6c3-72f1-b192-6cfa3f50b8f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherReceivablesNetCurrent_01a064cd-b6c3-7a79-ab76-fad0092ab9d5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherReceivablesNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_01a064cd-b6c3-79bf-95a5-d3372922f33e" xlink:to="loc_us-gaap_OtherReceivablesNetCurrent_01a064cd-b6c3-7a79-ab76-fad0092ab9d5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TemporaryEquityStockIssuedDuringPeriodSharesConversionOfDebt_01a064cd-b6c3-7224-8e9d-fbfff55dc91e" xlink:href="innv-20260930.xsd#innv_TemporaryEquityStockIssuedDuringPeriodSharesConversionOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_01a064cd-b6c3-79bf-95a5-d3372922f33e" xlink:to="loc_innv_TemporaryEquityStockIssuedDuringPeriodSharesConversionOfDebt_01a064cd-b6c3-7224-8e9d-fbfff55dc91e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TemporaryEquityStockIssuedDuringPeriodValueConversionOfDebt_01a064cd-b6c3-7e04-96cb-9755a716c636" xlink:href="innv-20260930.xsd#innv_TemporaryEquityStockIssuedDuringPeriodValueConversionOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_01a064cd-b6c3-79bf-95a5-d3372922f33e" xlink:to="loc_innv_TemporaryEquityStockIssuedDuringPeriodValueConversionOfDebt_01a064cd-b6c3-7e04-96cb-9755a716c636" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_01a1a893-10c2-71aa-937c-683d62b7f4df" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_01a064cd-b6c3-79bf-95a5-d3372922f33e" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_01a1a893-10c2-71aa-937c-683d62b7f4df" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_01a1a893-e1d8-73c0-9337-53bcc7fd4cc1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_01a064cd-b6c3-79bf-95a5-d3372922f33e" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_01a1a893-e1d8-73c0-9337-53bcc7fd4cc1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_01a1a894-2f56-73d0-ac59-2eba457907b7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_01a064cd-b6c3-79bf-95a5-d3372922f33e" xlink:to="loc_us-gaap_DebtInstrumentTerm_01a1a894-2f56-73d0-ac59-2eba457907b7" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/CommitmentsandContingenciesNarrativeDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#CommitmentsandContingenciesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/CommitmentsandContingenciesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsLineItems_01a064cd-b6c3-7806-9c81-a11acfcb8db9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherCommitmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsTable_01a064cd-b6c3-768e-9749-56206ddfe644" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherCommitmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_01a064cd-b6c3-7806-9c81-a11acfcb8db9" xlink:to="loc_us-gaap_OtherCommitmentsTable_01a064cd-b6c3-768e-9749-56206ddfe644" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_01a064cd-b6c3-7813-b606-70ee4b6ada1e" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OtherCommitmentsTable_01a064cd-b6c3-768e-9749-56206ddfe644" xlink:to="loc_srt_CounterpartyNameAxis_01a064cd-b6c3-7813-b606-70ee4b6ada1e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_01a064cd-b6c3-7813-b606-70ee4b6ada1e_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_01a064cd-b6c3-7813-b606-70ee4b6ada1e" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_01a064cd-b6c3-7813-b606-70ee4b6ada1e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_01a064cd-b6c3-754c-b4a7-f33d2f5db48b" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_01a064cd-b6c3-7813-b606-70ee4b6ada1e" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_01a064cd-b6c3-754c-b4a7-f33d2f5db48b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_FrameworkAgreementThirdPartyMember_01a064cd-b6c3-71f2-ab26-0d81a234bc31" xlink:href="innv-20260930.xsd#innv_FrameworkAgreementThirdPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_01a064cd-b6c3-754c-b4a7-f33d2f5db48b" xlink:to="loc_innv_FrameworkAgreementThirdPartyMember_01a064cd-b6c3-71f2-ab26-0d81a234bc31" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_FrameworkAgreementThirdPartyMinimumFeeDueYearOneMember_01a064cd-b6c3-7f49-83df-6ab409ec0e1a" xlink:href="innv-20260930.xsd#innv_FrameworkAgreementThirdPartyMinimumFeeDueYearOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_01a064cd-b6c3-754c-b4a7-f33d2f5db48b" xlink:to="loc_innv_FrameworkAgreementThirdPartyMinimumFeeDueYearOneMember_01a064cd-b6c3-7f49-83df-6ab409ec0e1a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_FrameworkAgreementThirdPartyMinimumFeeDueYearTwoMember_01a064cd-b6c3-7984-89d3-736fbbfec761" xlink:href="innv-20260930.xsd#innv_FrameworkAgreementThirdPartyMinimumFeeDueYearTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_01a064cd-b6c3-754c-b4a7-f33d2f5db48b" xlink:to="loc_innv_FrameworkAgreementThirdPartyMinimumFeeDueYearTwoMember_01a064cd-b6c3-7984-89d3-736fbbfec761" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_01a1a889-5beb-7d81-965b-337cd35e9786" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OtherCommitmentsTable_01a064cd-b6c3-768e-9749-56206ddfe644" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_01a1a889-5beb-7d81-965b-337cd35e9786" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_01a1a889-5beb-7d81-965b-337cd35e9786_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_01a1a889-5beb-7d81-965b-337cd35e9786" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_01a1a889-5beb-7d81-965b-337cd35e9786_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_01a1a889-5beb-7037-9608-ca3cf988b021" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_01a1a889-5beb-7d81-965b-337cd35e9786" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_01a1a889-5beb-7037-9608-ca3cf988b021" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_01a1a889-9641-74f7-9f23-11b588a0b761" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_01a1a889-5beb-7037-9608-ca3cf988b021" xlink:to="loc_us-gaap_SubsequentEventMember_01a1a889-9641-74f7-9f23-11b588a0b761" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsMaximumExposure_01a064cd-b6c3-7e1f-97eb-531a4213a281" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GuaranteeObligationsMaximumExposure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_01a064cd-b6c3-7806-9c81-a11acfcb8db9" xlink:to="loc_us-gaap_GuaranteeObligationsMaximumExposure_01a064cd-b6c3-7e1f-97eb-531a4213a281" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_PaymentsForGuarantorObligations_01a064cd-b6c3-727b-89ed-8cd55e2b78b2" xlink:href="innv-20260930.xsd#innv_PaymentsForGuarantorObligations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_01a064cd-b6c3-7806-9c81-a11acfcb8db9" xlink:to="loc_innv_PaymentsForGuarantorObligations_01a064cd-b6c3-727b-89ed-8cd55e2b78b2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsCurrentCarryingValue_01a064cd-b6c3-76bc-aec3-ce9bc2df1b89" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GuaranteeObligationsCurrentCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_01a064cd-b6c3-7806-9c81-a11acfcb8db9" xlink:to="loc_us-gaap_GuaranteeObligationsCurrentCarryingValue_01a064cd-b6c3-76bc-aec3-ce9bc2df1b89" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_IntangibleAssetsNumberOfPurchaseAgreements_01a064cd-b6c3-7ff8-ab40-1ef6084b7360" xlink:href="innv-20260930.xsd#innv_IntangibleAssetsNumberOfPurchaseAgreements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_01a064cd-b6c3-7806-9c81-a11acfcb8db9" xlink:to="loc_innv_IntangibleAssetsNumberOfPurchaseAgreements_01a064cd-b6c3-7ff8-ab40-1ef6084b7360" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_LicenseAgreementTransferFee_01a064cd-b6c3-7603-8f2a-ba3a0831f6a2" xlink:href="innv-20260930.xsd#innv_LicenseAgreementTransferFee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_01a064cd-b6c3-7806-9c81-a11acfcb8db9" xlink:to="loc_innv_LicenseAgreementTransferFee_01a064cd-b6c3-7603-8f2a-ba3a0831f6a2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRoyalties_01a064cd-b6c3-7c27-9c49-8b380996386f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsForRoyalties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_01a064cd-b6c3-7806-9c81-a11acfcb8db9" xlink:to="loc_us-gaap_PaymentsForRoyalties_01a064cd-b6c3-7c27-9c49-8b380996386f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ResearchAndDevelopmentAgreementMinimumFeeDueYearOne_01a064cd-b6c3-7f22-8c9a-db40d1602c0b" xlink:href="innv-20260930.xsd#innv_ResearchAndDevelopmentAgreementMinimumFeeDueYearOne"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_01a064cd-b6c3-7806-9c81-a11acfcb8db9" xlink:to="loc_innv_ResearchAndDevelopmentAgreementMinimumFeeDueYearOne_01a064cd-b6c3-7f22-8c9a-db40d1602c0b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_ResearchAndDevelopmentAgreementMinimumFeeDueYearTwo_01a064cd-b6c3-7b94-a230-83ac175a56d0" xlink:href="innv-20260930.xsd#innv_ResearchAndDevelopmentAgreementMinimumFeeDueYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_01a064cd-b6c3-7806-9c81-a11acfcb8db9" xlink:to="loc_innv_ResearchAndDevelopmentAgreementMinimumFeeDueYearTwo_01a064cd-b6c3-7b94-a230-83ac175a56d0" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_PaymentsForResearchAndDevelopment_01a064cd-b6c3-7b98-b25e-acd151b35960" xlink:href="innv-20260930.xsd#innv_PaymentsForResearchAndDevelopment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_01a064cd-b6c3-7806-9c81-a11acfcb8db9" xlink:to="loc_innv_PaymentsForResearchAndDevelopment_01a064cd-b6c3-7b98-b25e-acd151b35960" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_01a064cd-b6c3-72cd-bfc6-4b7cfaf2b910" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_01a064cd-b6c3-7806-9c81-a11acfcb8db9" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_01a064cd-b6c3-72cd-bfc6-4b7cfaf2b910" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_LossContingencyNumberOfMotionsOfAppointment_01a1cc06-8916-7a45-8372-efe682a48ff5" xlink:href="innv-20260930.xsd#innv_LossContingencyNumberOfMotionsOfAppointment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsLineItems_01a064cd-b6c3-7806-9c81-a11acfcb8db9" xlink:to="loc_innv_LossContingencyNumberOfMotionsOfAppointment_01a1cc06-8916-7a45-8372-efe682a48ff5" xlink:type="arc" order="10"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/BusinessSegmentDataTechnologySegmentInformationDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#BusinessSegmentDataTechnologySegmentInformationDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/BusinessSegmentDataTechnologySegmentInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-78a7-89d4-8b75afaa615c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_01a064cd-b6c3-7a60-bceb-170197b89ccc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-78a7-89d4-8b75afaa615c" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_01a064cd-b6c3-7a60-bceb-170197b89ccc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_01a064cd-b6c3-7866-958f-623d21c74346" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_01a064cd-b6c3-7a60-bceb-170197b89ccc" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_01a064cd-b6c3-7866-958f-623d21c74346" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_01a064cd-b6c3-7866-958f-623d21c74346_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_01a064cd-b6c3-7866-958f-623d21c74346" xlink:to="loc_us-gaap_SegmentDomain_01a064cd-b6c3-7866-958f-623d21c74346_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_01a064cd-b6c3-7439-8502-0d42c033c5fd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_01a064cd-b6c3-7866-958f-623d21c74346" xlink:to="loc_us-gaap_SegmentDomain_01a064cd-b6c3-7439-8502-0d42c033c5fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TechnologySegmentMember_01a064cd-b6c3-77f2-99c0-dfd03f2c0bb4" xlink:href="innv-20260930.xsd#innv_TechnologySegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_01a064cd-b6c3-7439-8502-0d42c033c5fd" xlink:to="loc_innv_TechnologySegmentMember_01a064cd-b6c3-77f2-99c0-dfd03f2c0bb4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_01a064cd-b6c3-721f-8ad9-93fe4a7bd417" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-78a7-89d4-8b75afaa615c" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_01a064cd-b6c3-721f-8ad9-93fe4a7bd417" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeInterest_01a064cd-b6c3-7bc2-ac3d-d23f84bb13db" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentIncomeInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-78a7-89d4-8b75afaa615c" xlink:to="loc_us-gaap_InvestmentIncomeInterest_01a064cd-b6c3-7bc2-ac3d-d23f84bb13db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_01a064cd-b6c3-77e0-b0ad-e7e747dfc04d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-78a7-89d4-8b75afaa615c" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_01a064cd-b6c3-77e0-b0ad-e7e747dfc04d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CompensationExpenseExcludingCostOfGoodAndServiceSold_01a064cd-b6c3-7913-8808-04fa40e8aaff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CompensationExpenseExcludingCostOfGoodAndServiceSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-78a7-89d4-8b75afaa615c" xlink:to="loc_us-gaap_CompensationExpenseExcludingCostOfGoodAndServiceSold_01a064cd-b6c3-7913-8808-04fa40e8aaff" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_FacilitiesEquipmentAndSupplies_01a064cd-b6c3-7b85-9dcf-3c5336ec6e89" xlink:href="innv-20260930.xsd#innv_FacilitiesEquipmentAndSupplies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-78a7-89d4-8b75afaa615c" xlink:to="loc_innv_FacilitiesEquipmentAndSupplies_01a064cd-b6c3-7b85-9dcf-3c5336ec6e89" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_01a064cd-b6c3-7c2d-9b2e-15a103bd69f1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-78a7-89d4-8b75afaa615c" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_01a064cd-b6c3-7c2d-9b2e-15a103bd69f1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfessionalFees_01a064cd-b6c3-745a-bf04-cf31fb2a2888" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfessionalFees"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-78a7-89d4-8b75afaa615c" xlink:to="loc_us-gaap_ProfessionalFees_01a064cd-b6c3-745a-bf04-cf31fb2a2888" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_01a064cd-b6c3-7368-87e8-9bbb31a08ff1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-78a7-89d4-8b75afaa615c" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_01a064cd-b6c3-7368-87e8-9bbb31a08ff1" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingAndMarketingExpense_01a064cd-b6c3-7554-bf0b-5168ddc085a3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SellingAndMarketingExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-78a7-89d4-8b75afaa615c" xlink:to="loc_us-gaap_SellingAndMarketingExpense_01a064cd-b6c3-7554-bf0b-5168ddc085a3" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationNonproduction_01a064cd-b6c3-7835-8c78-d3ef2c66ef1e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepreciationNonproduction"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-78a7-89d4-8b75afaa615c" xlink:to="loc_us-gaap_DepreciationNonproduction_01a064cd-b6c3-7835-8c78-d3ef2c66ef1e" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseNonoperating_01a064cd-b6c3-7eab-b1b5-41b028c9b2e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseNonoperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-78a7-89d4-8b75afaa615c" xlink:to="loc_us-gaap_InterestExpenseNonoperating_01a064cd-b6c3-7eab-b1b5-41b028c9b2e3" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_01a064cd-b6c3-7eac-ad95-a577c46cfbce" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-78a7-89d4-8b75afaa615c" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_01a064cd-b6c3-7eac-ad95-a577c46cfbce" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_01a064cd-b6c3-735e-92a5-9b742c7b2e1c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-78a7-89d4-8b75afaa615c" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_01a064cd-b6c3-735e-92a5-9b742c7b2e1c" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_01a064cd-b6c3-707a-8d94-8dd28752f179" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-78a7-89d4-8b75afaa615c" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_01a064cd-b6c3-707a-8d94-8dd28752f179" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_CostsAndExpensesAndNonoperatingIncomeExpense_01a064cd-b6c3-7c27-97b0-2298bb264045" xlink:href="innv-20260930.xsd#innv_CostsAndExpensesAndNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-78a7-89d4-8b75afaa615c" xlink:to="loc_innv_CostsAndExpensesAndNonoperatingIncomeExpense_01a064cd-b6c3-7c27-97b0-2298bb264045" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_01a064cd-b6c3-742b-8ac8-0ff0a856f98b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-78a7-89d4-8b75afaa615c" xlink:to="loc_us-gaap_NetIncomeLoss_01a064cd-b6c3-742b-8ac8-0ff0a856f98b" xlink:type="arc" order="15"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.innventure.com/role/BusinessSegmentDataReconciliationofSegmentInformationDetails" xlink:type="simple" xlink:href="innv-20260930.xsd#BusinessSegmentDataReconciliationofSegmentInformationDetails"/>
  <link:definitionLink xlink:role="http://www.innventure.com/role/BusinessSegmentDataReconciliationofSegmentInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-7cf1-9303-782b16c30a52" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_01a064cd-b6c3-7448-bd8a-01770c807cfd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-7cf1-9303-782b16c30a52" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_01a064cd-b6c3-7448-bd8a-01770c807cfd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_01a064cd-b6c3-79df-ae1b-50384db2734c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_01a064cd-b6c3-7448-bd8a-01770c807cfd" xlink:to="loc_srt_ConsolidationItemsAxis_01a064cd-b6c3-79df-ae1b-50384db2734c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_01a064cd-b6c3-79df-ae1b-50384db2734c_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_01a064cd-b6c3-79df-ae1b-50384db2734c" xlink:to="loc_srt_ConsolidationItemsDomain_01a064cd-b6c3-79df-ae1b-50384db2734c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_01a064cd-b6c3-7abf-875e-d156ed96babe" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_01a064cd-b6c3-79df-ae1b-50384db2734c" xlink:to="loc_srt_ConsolidationItemsDomain_01a064cd-b6c3-7abf-875e-d156ed96babe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_01a064cd-b6c3-7c43-9f05-63909da9e64c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_01a064cd-b6c3-7abf-875e-d156ed96babe" xlink:to="loc_us-gaap_OperatingSegmentsMember_01a064cd-b6c3-7c43-9f05-63909da9e64c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_01a064cd-b6c3-7a35-b674-16be39cc290a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_01a064cd-b6c3-7abf-875e-d156ed96babe" xlink:to="loc_us-gaap_CorporateNonSegmentMember_01a064cd-b6c3-7a35-b674-16be39cc290a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntersegmentEliminationMember_01a064cd-b6c3-775d-b917-cd668d34e63f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IntersegmentEliminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_01a064cd-b6c3-7abf-875e-d156ed96babe" xlink:to="loc_us-gaap_IntersegmentEliminationMember_01a064cd-b6c3-775d-b917-cd668d34e63f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_01a064cd-b6c3-7fde-9e5b-b1c0a2eef525" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_01a064cd-b6c3-7448-bd8a-01770c807cfd" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_01a064cd-b6c3-7fde-9e5b-b1c0a2eef525" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_01a064cd-b6c3-7fde-9e5b-b1c0a2eef525_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_01a064cd-b6c3-7fde-9e5b-b1c0a2eef525" xlink:to="loc_us-gaap_SegmentDomain_01a064cd-b6c3-7fde-9e5b-b1c0a2eef525_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_01a064cd-b6c3-721e-8e1b-bb1183a82f4f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_01a064cd-b6c3-7fde-9e5b-b1c0a2eef525" xlink:to="loc_us-gaap_SegmentDomain_01a064cd-b6c3-721e-8e1b-bb1183a82f4f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_innv_TechnologySegmentMember_01a064cd-b6c3-7e55-975a-9212c5b64e08" xlink:href="innv-20260930.xsd#innv_TechnologySegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_01a064cd-b6c3-721e-8e1b-bb1183a82f4f" xlink:to="loc_innv_TechnologySegmentMember_01a064cd-b6c3-7e55-975a-9212c5b64e08" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_01a064cd-b6c3-72a4-bc6d-4148fae18a88" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-7cf1-9303-782b16c30a52" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_01a064cd-b6c3-72a4-bc6d-4148fae18a88" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseNonoperating_01a064cd-b6c3-7cfa-ac5a-d9302a792674" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseNonoperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-7cf1-9303-782b16c30a52" xlink:to="loc_us-gaap_InterestExpenseNonoperating_01a064cd-b6c3-7cfa-ac5a-d9302a792674" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeInterest_01a064cd-b6c3-7675-9b60-c4cf2fbe8e52" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentIncomeInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-7cf1-9303-782b16c30a52" xlink:to="loc_us-gaap_InvestmentIncomeInterest_01a064cd-b6c3-7675-9b60-c4cf2fbe8e52" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_01a064cd-b6c3-77e8-bd36-a43bdd5a8cb4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-7cf1-9303-782b16c30a52" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_01a064cd-b6c3-77e8-bd36-a43bdd5a8cb4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_01a064cd-b6c3-741b-b4a5-4c280d00e46e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-7cf1-9303-782b16c30a52" xlink:to="loc_us-gaap_ProfitLoss_01a064cd-b6c3-741b-b4a5-4c280d00e46e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentExpenditureAdditionToLongLivedAssets_01a064cd-b6c3-784b-9b7d-5bd940887c17" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentExpenditureAdditionToLongLivedAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a064cd-b6c3-7cf1-9303-782b16c30a52" xlink:to="loc_us-gaap_SegmentExpenditureAdditionToLongLivedAssets_01a064cd-b6c3-784b-9b7d-5bd940887c17" xlink:type="arc" order="5"/>
  </link:definitionLink>
</link:linkbase>
