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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2025 Workiva-->
<!--r:d7392f3a-013f-4d0d-966f-3e01de4d5d71,g:27695480-9bbb-406e-97a3-bee01d8a1da3-->
<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://integralife.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCHANGESINSHAREHOLDERSEQUITYUNAUDITED" xlink:type="simple" xlink:href="iart-20250930.xsd#CONDENSEDCONSOLIDATEDSTATEMENTSOFCHANGESINSHAREHOLDERSEQUITYUNAUDITED"/>
  <link:definitionLink xlink:role="http://integralife.com/role/CONDENSEDCONSOLIDATEDSTATEMENTSOFCHANGESINSHAREHOLDERSEQUITYUNAUDITED" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_380c7361-700f-4438-8cb2-cfb44ab51aa1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_f71f65f4-0929-42ba-896f-6cc7dcf5a5bd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_380c7361-700f-4438-8cb2-cfb44ab51aa1" xlink:to="loc_us-gaap_StatementTable_f71f65f4-0929-42ba-896f-6cc7dcf5a5bd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_dec59329-fc63-4de4-86cf-87be48c9d4a9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_f71f65f4-0929-42ba-896f-6cc7dcf5a5bd" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_dec59329-fc63-4de4-86cf-87be48c9d4a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_dec59329-fc63-4de4-86cf-87be48c9d4a9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_dec59329-fc63-4de4-86cf-87be48c9d4a9" xlink:to="loc_us-gaap_EquityComponentDomain_dec59329-fc63-4de4-86cf-87be48c9d4a9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_172478ac-3948-4502-ad2d-380f05beee0e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_dec59329-fc63-4de4-86cf-87be48c9d4a9" xlink:to="loc_us-gaap_EquityComponentDomain_172478ac-3948-4502-ad2d-380f05beee0e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_177b3b97-7574-4773-bae2-2532abac3fdb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_172478ac-3948-4502-ad2d-380f05beee0e" xlink:to="loc_us-gaap_CommonStockMember_177b3b97-7574-4773-bae2-2532abac3fdb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_8cab88e7-a325-42c7-b138-57560e0c821e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockCommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_172478ac-3948-4502-ad2d-380f05beee0e" xlink:to="loc_us-gaap_TreasuryStockCommonMember_8cab88e7-a325-42c7-b138-57560e0c821e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_509c93ae-6229-4bdb-a5ea-669986dcec43" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_172478ac-3948-4502-ad2d-380f05beee0e" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_509c93ae-6229-4bdb-a5ea-669986dcec43" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_f7048646-c345-48fd-ab41-9f28dd055bc1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_172478ac-3948-4502-ad2d-380f05beee0e" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_f7048646-c345-48fd-ab41-9f28dd055bc1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_a4143b90-15a5-43e2-ab8d-96a8126f59e6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_172478ac-3948-4502-ad2d-380f05beee0e" xlink:to="loc_us-gaap_RetainedEarningsMember_a4143b90-15a5-43e2-ab8d-96a8126f59e6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_f33a2bc2-0c62-4343-a58c-2df7a368a1c3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_380c7361-700f-4438-8cb2-cfb44ab51aa1" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_f33a2bc2-0c62-4343-a58c-2df7a368a1c3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesIssued_f599aac8-74a1-46e9-b7a8-4e00af3cf270" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_f33a2bc2-0c62-4343-a58c-2df7a368a1c3" xlink:to="loc_us-gaap_SharesIssued_f599aac8-74a1-46e9-b7a8-4e00af3cf270" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_1858687b-8b6f-4783-86d6-0d1c1b4788a3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_f33a2bc2-0c62-4343-a58c-2df7a368a1c3" xlink:to="loc_us-gaap_StockholdersEquity_1858687b-8b6f-4783-86d6-0d1c1b4788a3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_1b68671f-4343-43b9-a975-e793b7d4c3d4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockCommonShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_f33a2bc2-0c62-4343-a58c-2df7a368a1c3" xlink:to="loc_us-gaap_TreasuryStockCommonShares_1b68671f-4343-43b9-a975-e793b7d4c3d4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_77ae4b8c-bcb3-412e-adcd-77853439a0e2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_f33a2bc2-0c62-4343-a58c-2df7a368a1c3" xlink:to="loc_us-gaap_NetIncomeLoss_77ae4b8c-bcb3-412e-adcd-77853439a0e2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_e2a4b689-b3b5-403c-a4d6-ab1dcb5be43e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_f33a2bc2-0c62-4343-a58c-2df7a368a1c3" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_e2a4b689-b3b5-403c-a4d6-ab1dcb5be43e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_2d0b4b60-cf37-4899-82c9-1cce630a9a96" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_f33a2bc2-0c62-4343-a58c-2df7a368a1c3" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_2d0b4b60-cf37-4899-82c9-1cce630a9a96" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_e0ae618d-2f84-45f5-977d-227c7a9954c3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_f33a2bc2-0c62-4343-a58c-2df7a368a1c3" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_e0ae618d-2f84-45f5-977d-227c7a9954c3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_8b7f4968-c69a-4476-a06d-e3874119f72e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_f33a2bc2-0c62-4343-a58c-2df7a368a1c3" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_8b7f4968-c69a-4476-a06d-e3874119f72e" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_SharesIssuedSharesShareBasedPaymentArrangementNetOfSharesWithheldForTaxesAndForfeitures_caa276b1-d190-4cee-b7db-fca8cd2564f6" xlink:href="iart-20250930.xsd#iart_SharesIssuedSharesShareBasedPaymentArrangementNetOfSharesWithheldForTaxesAndForfeitures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_f33a2bc2-0c62-4343-a58c-2df7a368a1c3" xlink:to="loc_iart_SharesIssuedSharesShareBasedPaymentArrangementNetOfSharesWithheldForTaxesAndForfeitures_caa276b1-d190-4cee-b7db-fca8cd2564f6" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_f7d04a98-52fb-4dfb-85fb-4191c976da11" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_f33a2bc2-0c62-4343-a58c-2df7a368a1c3" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_f7d04a98-52fb-4dfb-85fb-4191c976da11" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_APICShareBasedPaymentArrangementIncreaseForCostRecognitionAndOtherAdjustments_1934b01e-a223-436c-b1a3-2e4bb332ec79" xlink:href="iart-20250930.xsd#iart_APICShareBasedPaymentArrangementIncreaseForCostRecognitionAndOtherAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_f33a2bc2-0c62-4343-a58c-2df7a368a1c3" xlink:to="loc_iart_APICShareBasedPaymentArrangementIncreaseForCostRecognitionAndOtherAdjustments_1934b01e-a223-436c-b1a3-2e4bb332ec79" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_587ee419-9712-45a9-bb82-3a97d0fed452" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_f33a2bc2-0c62-4343-a58c-2df7a368a1c3" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_587ee419-9712-45a9-bb82-3a97d0fed452" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityOther_19798a69-3f51-424b-a8e4-0c9df1eec3f2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_f33a2bc2-0c62-4343-a58c-2df7a368a1c3" xlink:to="loc_us-gaap_StockholdersEquityOther_19798a69-3f51-424b-a8e4-0c9df1eec3f2" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodShares_861b3b34-ba5c-456c-a36b-5865684191d8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockRepurchasedDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_f33a2bc2-0c62-4343-a58c-2df7a368a1c3" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodShares_861b3b34-ba5c-456c-a36b-5865684191d8" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodValue_b3821da2-1c85-45b9-b092-8c6ab76df7ab" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockRepurchasedDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_f33a2bc2-0c62-4343-a58c-2df7a368a1c3" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodValue_b3821da2-1c85-45b9-b092-8c6ab76df7ab" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesIssued_d0d287fd-d90c-4dec-bbb5-cc80f16c91c7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharesIssued"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_41480f50-a71f-42a6-b1ad-c6e46e638ddf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_1f6057c4-2f40-4130-8390-f700f075db6b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockCommonShares"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/BASISOFPRESENTATIONScheduleofRestructuringChargesDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#BASISOFPRESENTATIONScheduleofRestructuringChargesDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/BASISOFPRESENTATIONScheduleofRestructuringChargesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_4c3abe7d-7c44-4c8d-99b9-8be39cc41725" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringCostAndReserveLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_ea41c2f0-8105-4398-9ee1-df98911e409b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_4c3abe7d-7c44-4c8d-99b9-8be39cc41725" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_ea41c2f0-8105-4398-9ee1-df98911e409b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_6864f6d5-61fc-482d-8ccb-ee069a5d1201" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_ea41c2f0-8105-4398-9ee1-df98911e409b" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_6864f6d5-61fc-482d-8ccb-ee069a5d1201" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_6864f6d5-61fc-482d-8ccb-ee069a5d1201_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_6864f6d5-61fc-482d-8ccb-ee069a5d1201" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_6864f6d5-61fc-482d-8ccb-ee069a5d1201_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_0d8caca3-5bcb-4aa6-b904-d1e219241cfb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_6864f6d5-61fc-482d-8ccb-ee069a5d1201" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_0d8caca3-5bcb-4aa6-b904-d1e219241cfb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfSalesMember_8af58a77-33e9-4bb8-a63e-dbed64240d49" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostOfSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_0d8caca3-5bcb-4aa6-b904-d1e219241cfb" xlink:to="loc_us-gaap_CostOfSalesMember_8af58a77-33e9-4bb8-a63e-dbed64240d49" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember_a22ac7ae-645c-443e-b37e-29144be108bf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ResearchAndDevelopmentExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_0d8caca3-5bcb-4aa6-b904-d1e219241cfb" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseMember_a22ac7ae-645c-443e-b37e-29144be108bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_f60339f4-5717-477a-b3cb-8bcc4fc3f974" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_0d8caca3-5bcb-4aa6-b904-d1e219241cfb" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_f60339f4-5717-477a-b3cb-8bcc4fc3f974" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserveRollForward_27c7da9d-f631-46ed-bddd-22bd89d2dca9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringReserveRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_4c3abe7d-7c44-4c8d-99b9-8be39cc41725" xlink:to="loc_us-gaap_RestructuringReserveRollForward_27c7da9d-f631-46ed-bddd-22bd89d2dca9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserve_5aba8cd7-3046-47f0-9058-6d73acfd1c0c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringReserve"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_27c7da9d-f631-46ed-bddd-22bd89d2dca9" xlink:to="loc_us-gaap_RestructuringReserve_5aba8cd7-3046-47f0-9058-6d73acfd1c0c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_d48bc7d9-eb65-43c8-8af9-58c8df9d04ca" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_27c7da9d-f631-46ed-bddd-22bd89d2dca9" xlink:to="loc_us-gaap_RestructuringCharges_d48bc7d9-eb65-43c8-8af9-58c8df9d04ca" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringIncurredCostStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration_6d4ece84-1412-4a84-b129-47f2b9819ba8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringIncurredCostStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_27c7da9d-f631-46ed-bddd-22bd89d2dca9" xlink:to="loc_us-gaap_RestructuringIncurredCostStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration_6d4ece84-1412-4a84-b129-47f2b9819ba8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserveAccrualAdjustment1_eb6f7ff6-ffff-4d66-b12b-ffafcbaf72f6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringReserveAccrualAdjustment1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_27c7da9d-f631-46ed-bddd-22bd89d2dca9" xlink:to="loc_us-gaap_RestructuringReserveAccrualAdjustment1_eb6f7ff6-ffff-4d66-b12b-ffafcbaf72f6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserve_8ac96a8d-567f-4220-bbab-6b65d21ac9e2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringReserve"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/ACQUISITIONSANDDIVESTITURESNarrativeDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#ACQUISITIONSANDDIVESTITURESNarrativeDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/ACQUISITIONSANDDIVESTITURESNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_9dc982d0-3fc5-4c76-8418-672f70dcb495" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_b359700d-42b3-4435-9266-9177aa3e52b3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9dc982d0-3fc5-4c76-8418-672f70dcb495" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_b359700d-42b3-4435-9266-9177aa3e52b3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionAxis_fc38c4ae-e1e2-4c3c-8580-b976a7ecba8c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_b359700d-42b3-4435-9266-9177aa3e52b3" xlink:to="loc_us-gaap_AssetAcquisitionAxis_fc38c4ae-e1e2-4c3c-8580-b976a7ecba8c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionDomain_fc38c4ae-e1e2-4c3c-8580-b976a7ecba8c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetAcquisitionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AssetAcquisitionAxis_fc38c4ae-e1e2-4c3c-8580-b976a7ecba8c" xlink:to="loc_us-gaap_AssetAcquisitionDomain_fc38c4ae-e1e2-4c3c-8580-b976a7ecba8c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionDomain_b68ad6d3-8fea-45c5-a1e6-9bb69fcfa778" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetAcquisitionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AssetAcquisitionAxis_fc38c4ae-e1e2-4c3c-8580-b976a7ecba8c" xlink:to="loc_us-gaap_AssetAcquisitionDomain_b68ad6d3-8fea-45c5-a1e6-9bb69fcfa778" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DurepairRegenerationMatrixMember_d4a3a163-34c7-4d2c-831e-7fd2b060ad18" xlink:href="iart-20250930.xsd#iart_DurepairRegenerationMatrixMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetAcquisitionDomain_b68ad6d3-8fea-45c5-a1e6-9bb69fcfa778" xlink:to="loc_iart_DurepairRegenerationMatrixMember_d4a3a163-34c7-4d2c-831e-7fd2b060ad18" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementScenarioAxis_fcb7ae8f-1f3c-438e-9eae-ed146314163e" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_StatementScenarioAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_b359700d-42b3-4435-9266-9177aa3e52b3" xlink:to="loc_srt_StatementScenarioAxis_fcb7ae8f-1f3c-438e-9eae-ed146314163e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_fcb7ae8f-1f3c-438e-9eae-ed146314163e_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_fcb7ae8f-1f3c-438e-9eae-ed146314163e" xlink:to="loc_srt_ScenarioUnspecifiedDomain_fcb7ae8f-1f3c-438e-9eae-ed146314163e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_7c87aa76-115b-4a29-bafc-03fd0be725ad" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_fcb7ae8f-1f3c-438e-9eae-ed146314163e" xlink:to="loc_srt_ScenarioUnspecifiedDomain_7c87aa76-115b-4a29-bafc-03fd0be725ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioForecastMember_dda018e3-a0cf-44b8-a86b-00f52679caf3" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ScenarioForecastMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_7c87aa76-115b-4a29-bafc-03fd0be725ad" xlink:to="loc_srt_ScenarioForecastMember_dda018e3-a0cf-44b8-a86b-00f52679caf3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_3f2e843e-1a68-4b94-ad6b-d00032a582dc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_b359700d-42b3-4435-9266-9177aa3e52b3" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_3f2e843e-1a68-4b94-ad6b-d00032a582dc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_3f2e843e-1a68-4b94-ad6b-d00032a582dc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_3f2e843e-1a68-4b94-ad6b-d00032a582dc" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_3f2e843e-1a68-4b94-ad6b-d00032a582dc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_d9a60d5d-f6f4-4cb7-93b8-e143ae9dfa01" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_3f2e843e-1a68-4b94-ad6b-d00032a582dc" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_d9a60d5d-f6f4-4cb7-93b8-e143ae9dfa01" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_AcclarentInc.Member_5930d2c9-baf9-482b-93f8-4585350a7d5c" xlink:href="iart-20250930.xsd#iart_AcclarentInc.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_d9a60d5d-f6f4-4cb7-93b8-e143ae9dfa01" xlink:to="loc_iart_AcclarentInc.Member_5930d2c9-baf9-482b-93f8-4585350a7d5c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetAcquisitionConsiderationTransferred_618c4513-a1b8-43ff-9780-2e1d6d7256b1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetAcquisitionConsiderationTransferred"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9dc982d0-3fc5-4c76-8418-672f70dcb495" xlink:to="loc_us-gaap_AssetAcquisitionConsiderationTransferred_618c4513-a1b8-43ff-9780-2e1d6d7256b1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_PaymentsForAssetAcquisitions_0f1e6b1e-ea56-49dd-b9b8-2dafbbc913b8" xlink:href="iart-20250930.xsd#iart_PaymentsForAssetAcquisitions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9dc982d0-3fc5-4c76-8418-672f70dcb495" xlink:to="loc_iart_PaymentsForAssetAcquisitions_0f1e6b1e-ea56-49dd-b9b8-2dafbbc913b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_3a857644-e84b-416f-98e5-2389ceff5b5d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9dc982d0-3fc5-4c76-8418-672f70dcb495" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_3a857644-e84b-416f-98e5-2389ceff5b5d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentConsiderationTransferred_5ff7be98-d020-4ed8-9147-a59566c3b6da" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentConsiderationTransferred"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9dc982d0-3fc5-4c76-8418-672f70dcb495" xlink:to="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentConsiderationTransferred_5ff7be98-d020-4ed8-9147-a59566c3b6da" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentDeferredTaxLiabilities_9ce1d927-8136-447b-bf05-95bf95dd5f16" xlink:href="iart-20250930.xsd#iart_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentDeferredTaxLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9dc982d0-3fc5-4c76-8418-672f70dcb495" xlink:to="loc_iart_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentDeferredTaxLiabilities_9ce1d927-8136-447b-bf05-95bf95dd5f16" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_6c30aa18-e150-4688-80e6-942b2deb6af9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9dc982d0-3fc5-4c76-8418-672f70dcb495" xlink:to="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_6c30aa18-e150-4688-80e6-942b2deb6af9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_BusinessCombinationIntangibleAssetAcquiredDiscountRate_922fd2ac-3cb3-4366-90b8-01447f02769d" xlink:href="iart-20250930.xsd#iart_BusinessCombinationIntangibleAssetAcquiredDiscountRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_9dc982d0-3fc5-4c76-8418-672f70dcb495" xlink:to="loc_iart_BusinessCombinationIntangibleAssetAcquiredDiscountRate_922fd2ac-3cb3-4366-90b8-01447f02769d" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/ACQUISITIONSANDDIVESTITURESBusinessCombinationScheduleofPurchasePriceAllocationDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#ACQUISITIONSANDDIVESTITURESBusinessCombinationScheduleofPurchasePriceAllocationDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/ACQUISITIONSANDDIVESTITURESBusinessCombinationScheduleofPurchasePriceAllocationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_ca84c8cd-f1cf-4063-9122-ecf8f74de310" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_eb228599-e864-4c43-a27f-826e082c602b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ca84c8cd-f1cf-4063-9122-ecf8f74de310" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_eb228599-e864-4c43-a27f-826e082c602b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_4c2faffe-6112-4178-bd98-7e4209d4ebcc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_eb228599-e864-4c43-a27f-826e082c602b" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_4c2faffe-6112-4178-bd98-7e4209d4ebcc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_4c2faffe-6112-4178-bd98-7e4209d4ebcc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_4c2faffe-6112-4178-bd98-7e4209d4ebcc" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_4c2faffe-6112-4178-bd98-7e4209d4ebcc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_e3dae493-0972-448e-860a-1d269d6c2ff3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_4c2faffe-6112-4178-bd98-7e4209d4ebcc" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_e3dae493-0972-448e-860a-1d269d6c2ff3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_AcclarentInc.Member_6d8375ef-8c98-4fef-a85d-5623648036e4" xlink:href="iart-20250930.xsd#iart_AcclarentInc.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_e3dae493-0972-448e-860a-1d269d6c2ff3" xlink:to="loc_iart_AcclarentInc.Member_6d8375ef-8c98-4fef-a85d-5623648036e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_7df64c72-892d-4b9f-9227-d2598f10ebfa" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_eb228599-e864-4c43-a27f-826e082c602b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_7df64c72-892d-4b9f-9227-d2598f10ebfa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_7df64c72-892d-4b9f-9227-d2598f10ebfa_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_7df64c72-892d-4b9f-9227-d2598f10ebfa" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_7df64c72-892d-4b9f-9227-d2598f10ebfa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_14d6cfb6-e0d3-4488-8db2-b4a514a98eb4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_7df64c72-892d-4b9f-9227-d2598f10ebfa" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_14d6cfb6-e0d3-4488-8db2-b4a514a98eb4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CompletedTechnologyMember_b53dd08f-a64f-4a59-87ae-027bfd5d2bbb" xlink:href="iart-20250930.xsd#iart_CompletedTechnologyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_14d6cfb6-e0d3-4488-8db2-b4a514a98eb4" xlink:to="loc_iart_CompletedTechnologyMember_b53dd08f-a64f-4a59-87ae-027bfd5d2bbb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TrademarksAndTradeNamesMember_3b0b5200-5845-404c-a97f-883a13da9c76" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TrademarksAndTradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_14d6cfb6-e0d3-4488-8db2-b4a514a98eb4" xlink:to="loc_us-gaap_TrademarksAndTradeNamesMember_3b0b5200-5845-404c-a97f-883a13da9c76" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_8ac21da5-1bfb-44ae-9d55-e7b656c72f3a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_14d6cfb6-e0d3-4488-8db2-b4a514a98eb4" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_8ac21da5-1bfb-44ae-9d55-e7b656c72f3a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAbstract_1d4c0b3a-7d83-44e6-802d-b8466059dadc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ca84c8cd-f1cf-4063-9122-ecf8f74de310" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAbstract_1d4c0b3a-7d83-44e6-802d-b8466059dadc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_516e8d71-9b4c-4fa9-adb6-bd27ea716be8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAbstract_1d4c0b3a-7d83-44e6-802d-b8466059dadc" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_516e8d71-9b4c-4fa9-adb6-bd27ea716be8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_85d1c0ca-2609-47b9-89ab-a02694e72dd6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAbstract_1d4c0b3a-7d83-44e6-802d-b8466059dadc" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent_85d1c0ca-2609-47b9-89ab-a02694e72dd6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_17bc8335-121b-47e5-a6d5-b9cf13f4f9e3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAbstract_1d4c0b3a-7d83-44e6-802d-b8466059dadc" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_17bc8335-121b-47e5-a6d5-b9cf13f4f9e3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory_d82cf4b4-9276-4503-9997-7a3d5099ffdb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAbstract_1d4c0b3a-7d83-44e6-802d-b8466059dadc" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory_d82cf4b4-9276-4503-9997-7a3d5099ffdb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets_476b4461-d9af-47a3-ad72-f4e478a6bf7b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAbstract_1d4c0b3a-7d83-44e6-802d-b8466059dadc" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets_476b4461-d9af-47a3-ad72-f4e478a6bf7b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_3d737ad0-0cf9-40b1-bac3-9d6c302d9ba8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAbstract_1d4c0b3a-7d83-44e6-802d-b8466059dadc" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_3d737ad0-0cf9-40b1-bac3-9d6c302d9ba8" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets_19feea8c-2dd5-4336-81db-0210bb8a13ff" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsAbstract_1d4c0b3a-7d83-44e6-802d-b8466059dadc" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets_19feea8c-2dd5-4336-81db-0210bb8a13ff" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_4d11f3ba-b128-4c96-955a-7e1a2d70d731" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ca84c8cd-f1cf-4063-9122-ecf8f74de310" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_4d11f3ba-b128-4c96-955a-7e1a2d70d731" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRightOfUseAssetOperatingLeases_471be6e0-c5ac-4304-b4df-5ce77e2b2c45" xlink:href="iart-20250930.xsd#iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRightOfUseAssetOperatingLeases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ca84c8cd-f1cf-4063-9122-ecf8f74de310" xlink:to="loc_iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedRightOfUseAssetOperatingLeases_471be6e0-c5ac-4304-b4df-5ce77e2b2c45" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_2fffdc3d-453d-4327-9137-9a65e828b647" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ca84c8cd-f1cf-4063-9122-ecf8f74de310" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_2fffdc3d-453d-4327-9137-9a65e828b647" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_908335b8-731c-4cf8-9a87-35661ac40b2b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ca84c8cd-f1cf-4063-9122-ecf8f74de310" xlink:to="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_908335b8-731c-4cf8-9a87-35661ac40b2b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_0d2be309-59ca-4534-a35d-428e17a84c76" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ca84c8cd-f1cf-4063-9122-ecf8f74de310" xlink:to="loc_us-gaap_Goodwill_0d2be309-59ca-4534-a35d-428e17a84c76" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssets_9c8da628-de69-43b0-80d7-91259269d2ae" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ca84c8cd-f1cf-4063-9122-ecf8f74de310" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxAssets_9c8da628-de69-43b0-80d7-91259269d2ae" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedAssetsAcquiredIncludingGoodwill_1590adc8-eaf1-421e-9171-6789251ed60a" xlink:href="iart-20250930.xsd#iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedAssetsAcquiredIncludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ca84c8cd-f1cf-4063-9122-ecf8f74de310" xlink:to="loc_iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedAssetsAcquiredIncludingGoodwill_1590adc8-eaf1-421e-9171-6789251ed60a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAbstract_5122eeb3-ab85-4634-bf32-9a848b0e0f5d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ca84c8cd-f1cf-4063-9122-ecf8f74de310" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAbstract_5122eeb3-ab85-4634-bf32-9a848b0e0f5d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable_8edbb10d-5971-4c19-8784-3830c36badae" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAbstract_5122eeb3-ab85-4634-bf32-9a848b0e0f5d" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable_8edbb10d-5971-4c19-8784-3830c36badae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedContractWithCustomerLiabilityCurrent_62e57afb-6eb5-4f0b-acc9-e6ae1716dd2c" xlink:href="iart-20250930.xsd#iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedContractWithCustomerLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAbstract_5122eeb3-ab85-4634-bf32-9a848b0e0f5d" xlink:to="loc_iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedContractWithCustomerLiabilityCurrent_62e57afb-6eb5-4f0b-acc9-e6ae1716dd2c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesEmployeeRelatedLiabilities_0c90b737-db0e-481d-9191-4123044bed75" xlink:href="iart-20250930.xsd#iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesEmployeeRelatedLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAbstract_5122eeb3-ab85-4634-bf32-9a848b0e0f5d" xlink:to="loc_iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesEmployeeRelatedLiabilities_0c90b737-db0e-481d-9191-4123044bed75" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccruedLiabilities_d4014348-0042-4ba5-8e63-489b40d94fb1" xlink:href="iart-20250930.xsd#iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccruedLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAbstract_5122eeb3-ab85-4634-bf32-9a848b0e0f5d" xlink:to="loc_iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccruedLiabilities_d4014348-0042-4ba5-8e63-489b40d94fb1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesLeaseLiabilityOperatingLeases_386582b5-6b54-41a4-a01b-5019887fcd41" xlink:href="iart-20250930.xsd#iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesLeaseLiabilityOperatingLeases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAbstract_5122eeb3-ab85-4634-bf32-9a848b0e0f5d" xlink:to="loc_iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesLeaseLiabilityOperatingLeases_386582b5-6b54-41a4-a01b-5019887fcd41" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities_3ac0e7f6-f39b-4365-a5af-ac36fcc8d37e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAbstract_5122eeb3-ab85-4634-bf32-9a848b0e0f5d" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilities_3ac0e7f6-f39b-4365-a5af-ac36fcc8d37e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLeaseLiabilityOperatingLeases_8e654b32-b503-4c51-b1e8-c733adc8ea89" xlink:href="iart-20250930.xsd#iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLeaseLiabilityOperatingLeases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ca84c8cd-f1cf-4063-9122-ecf8f74de310" xlink:to="loc_iart_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLeaseLiabilityOperatingLeases_8e654b32-b503-4c51-b1e8-c733adc8ea89" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities_6c94265f-a5e9-40f7-ac9d-ff54d5c95d99" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ca84c8cd-f1cf-4063-9122-ecf8f74de310" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilities_6c94265f-a5e9-40f7-ac9d-ff54d5c95d99" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_bc43f022-192d-4c0f-bae6-53b9a0305ca6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ca84c8cd-f1cf-4063-9122-ecf8f74de310" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_bc43f022-192d-4c0f-bae6-53b9a0305ca6" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_aca52733-f52b-4c10-9fe7-6c2ca1ecb80f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ca84c8cd-f1cf-4063-9122-ecf8f74de310" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_aca52733-f52b-4c10-9fe7-6c2ca1ecb80f" xlink:type="arc" order="12"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/REVENUESFROMCONTRACTSWITHCUSTOMERSNarrativeDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#REVENUESFROMCONTRACTSWITHCUSTOMERSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/REVENUESFROMCONTRACTSWITHCUSTOMERSNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_92ee11df-64e9-44b3-a6bc-4f3bf7aec43d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_937983ae-0d23-4191-9adc-a5fee24b0a29" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_92ee11df-64e9-44b3-a6bc-4f3bf7aec43d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_937983ae-0d23-4191-9adc-a5fee24b0a29" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_5a13be35-9d31-461f-8cf0-11e6c38a9c2e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_937983ae-0d23-4191-9adc-a5fee24b0a29" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_5a13be35-9d31-461f-8cf0-11e6c38a9c2e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_ReturnPolicyIssueOfCreditNumberOfDaysFromShipment_72730ba8-b531-43b1-a977-f01c3244a660" xlink:href="iart-20250930.xsd#iart_ReturnPolicyIssueOfCreditNumberOfDaysFromShipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_92ee11df-64e9-44b3-a6bc-4f3bf7aec43d" xlink:to="loc_iart_ReturnPolicyIssueOfCreditNumberOfDaysFromShipment_72730ba8-b531-43b1-a977-f01c3244a660" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_66f523eb-b526-4074-bcc0-412d5251dc9d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_92ee11df-64e9-44b3-a6bc-4f3bf7aec43d" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_66f523eb-b526-4074-bcc0-412d5251dc9d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_2c9a0f11-3e63-44f5-957b-56fdf79575a6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_92ee11df-64e9-44b3-a6bc-4f3bf7aec43d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_2c9a0f11-3e63-44f5-957b-56fdf79575a6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_e3f17acd-29e0-4d39-be83-347a9adeda8b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_92ee11df-64e9-44b3-a6bc-4f3bf7aec43d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_e3f17acd-29e0-4d39-be83-347a9adeda8b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_ef3dd9c0-4c8d-476d-9cb6-4869af03828b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_92ee11df-64e9-44b3-a6bc-4f3bf7aec43d" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_ef3dd9c0-4c8d-476d-9cb6-4869af03828b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_RevenueProductWarrantyPeriod_eed88037-59e5-4c99-b9dc-590fc24bfdf6" xlink:href="iart-20250930.xsd#iart_RevenueProductWarrantyPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_92ee11df-64e9-44b3-a6bc-4f3bf7aec43d" xlink:to="loc_iart_RevenueProductWarrantyPeriod_eed88037-59e5-4c99-b9dc-590fc24bfdf6" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/REVENUESFROMCONTRACTSWITHCUSTOMERSNarrativeDetails_1" xlink:type="simple" xlink:href="iart-20250930.xsd#REVENUESFROMCONTRACTSWITHCUSTOMERSNarrativeDetails_1"/>
  <link:definitionLink xlink:role="http://integralife.com/role/REVENUESFROMCONTRACTSWITHCUSTOMERSNarrativeDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_92ee11df-64e9-44b3-a6bc-4f3bf7aec43d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_937983ae-0d23-4191-9adc-a5fee24b0a29" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_92ee11df-64e9-44b3-a6bc-4f3bf7aec43d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_937983ae-0d23-4191-9adc-a5fee24b0a29" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_ReturnPolicyIssueOfCreditNumberOfDaysFromShipment_72730ba8-b531-43b1-a977-f01c3244a660" xlink:href="iart-20250930.xsd#iart_ReturnPolicyIssueOfCreditNumberOfDaysFromShipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_92ee11df-64e9-44b3-a6bc-4f3bf7aec43d" xlink:to="loc_iart_ReturnPolicyIssueOfCreditNumberOfDaysFromShipment_72730ba8-b531-43b1-a977-f01c3244a660" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_66f523eb-b526-4074-bcc0-412d5251dc9d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_92ee11df-64e9-44b3-a6bc-4f3bf7aec43d" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_66f523eb-b526-4074-bcc0-412d5251dc9d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_2c9a0f11-3e63-44f5-957b-56fdf79575a6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_92ee11df-64e9-44b3-a6bc-4f3bf7aec43d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationPercentage_2c9a0f11-3e63-44f5-957b-56fdf79575a6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_e3f17acd-29e0-4d39-be83-347a9adeda8b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_92ee11df-64e9-44b3-a6bc-4f3bf7aec43d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_e3f17acd-29e0-4d39-be83-347a9adeda8b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_ef3dd9c0-4c8d-476d-9cb6-4869af03828b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_92ee11df-64e9-44b3-a6bc-4f3bf7aec43d" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_ef3dd9c0-4c8d-476d-9cb6-4869af03828b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_RevenueProductWarrantyPeriod_eed88037-59e5-4c99-b9dc-590fc24bfdf6" xlink:href="iart-20250930.xsd#iart_RevenueProductWarrantyPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_92ee11df-64e9-44b3-a6bc-4f3bf7aec43d" xlink:to="loc_iart_RevenueProductWarrantyPeriod_eed88037-59e5-4c99-b9dc-590fc24bfdf6" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/REVENUESFROMCONTRACTSWITHCUSTOMERSScheduleofRevenuesDisaggregatedbyMajorSourceDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#REVENUESFROMCONTRACTSWITHCUSTOMERSScheduleofRevenuesDisaggregatedbyMajorSourceDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/REVENUESFROMCONTRACTSWITHCUSTOMERSScheduleofRevenuesDisaggregatedbyMajorSourceDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_4e622113-856f-4a7e-8fb6-5f83cef3073b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_31618269-bf3b-49db-9f53-a716782304ad" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_4e622113-856f-4a7e-8fb6-5f83cef3073b" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_31618269-bf3b-49db-9f53-a716782304ad" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_ec1b1eb7-5557-49bd-b451-f9a6d0ae8b3e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_31618269-bf3b-49db-9f53-a716782304ad" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_ec1b1eb7-5557-49bd-b451-f9a6d0ae8b3e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_ec1b1eb7-5557-49bd-b451-f9a6d0ae8b3e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_ec1b1eb7-5557-49bd-b451-f9a6d0ae8b3e" xlink:to="loc_us-gaap_SegmentDomain_ec1b1eb7-5557-49bd-b451-f9a6d0ae8b3e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_cc9bb7e5-739c-48a8-9c84-fe890c70e468" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_ec1b1eb7-5557-49bd-b451-f9a6d0ae8b3e" xlink:to="loc_us-gaap_SegmentDomain_cc9bb7e5-739c-48a8-9c84-fe890c70e468" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CodmanSpecialtySurgicalMember_a45c4bfa-9c60-4bf8-9ba8-0fcafa0a46e4" xlink:href="iart-20250930.xsd#iart_CodmanSpecialtySurgicalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_cc9bb7e5-739c-48a8-9c84-fe890c70e468" xlink:to="loc_iart_CodmanSpecialtySurgicalMember_a45c4bfa-9c60-4bf8-9ba8-0fcafa0a46e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_TissueTechnologiesMember_0a050c85-f59f-4236-b7fb-ce1f196c481e" xlink:href="iart-20250930.xsd#iart_TissueTechnologiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_cc9bb7e5-739c-48a8-9c84-fe890c70e468" xlink:to="loc_iart_TissueTechnologiesMember_0a050c85-f59f-4236-b7fb-ce1f196c481e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_7ab667aa-5d2c-47c6-bb59-fcbcf4f8704e" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_31618269-bf3b-49db-9f53-a716782304ad" xlink:to="loc_srt_ProductOrServiceAxis_7ab667aa-5d2c-47c6-bb59-fcbcf4f8704e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_7ab667aa-5d2c-47c6-bb59-fcbcf4f8704e_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_7ab667aa-5d2c-47c6-bb59-fcbcf4f8704e" xlink:to="loc_srt_ProductsAndServicesDomain_7ab667aa-5d2c-47c6-bb59-fcbcf4f8704e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_86f9ea55-fe08-472b-af66-a06ec75eee08" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_7ab667aa-5d2c-47c6-bb59-fcbcf4f8704e" xlink:to="loc_srt_ProductsAndServicesDomain_86f9ea55-fe08-472b-af66-a06ec75eee08" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_NeurosurgeryMember_f50cefbc-a222-4485-840f-2bcee54d3f82" xlink:href="iart-20250930.xsd#iart_NeurosurgeryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_86f9ea55-fe08-472b-af66-a06ec75eee08" xlink:to="loc_iart_NeurosurgeryMember_f50cefbc-a222-4485-840f-2bcee54d3f82" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_InstrumentsMember_e3a68a3c-723e-421f-afe5-a94edecae652" xlink:href="iart-20250930.xsd#iart_InstrumentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_86f9ea55-fe08-472b-af66-a06ec75eee08" xlink:to="loc_iart_InstrumentsMember_e3a68a3c-723e-421f-afe5-a94edecae652" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_ENTMember_1a649be9-2ad1-4080-b1e9-12a081d292cc" xlink:href="iart-20250930.xsd#iart_ENTMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_86f9ea55-fe08-472b-af66-a06ec75eee08" xlink:to="loc_iart_ENTMember_1a649be9-2ad1-4080-b1e9-12a081d292cc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_RegenerativeSkinAndWoundMember_51fb6e6e-a037-4e59-82ae-569857d45a10" xlink:href="iart-20250930.xsd#iart_RegenerativeSkinAndWoundMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_86f9ea55-fe08-472b-af66-a06ec75eee08" xlink:to="loc_iart_RegenerativeSkinAndWoundMember_51fb6e6e-a037-4e59-82ae-569857d45a10" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_PrivateLabelMember_6686bfe9-c5ec-44da-b91d-6ad58b9ceb9d" xlink:href="iart-20250930.xsd#iart_PrivateLabelMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_86f9ea55-fe08-472b-af66-a06ec75eee08" xlink:to="loc_iart_PrivateLabelMember_6686bfe9-c5ec-44da-b91d-6ad58b9ceb9d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_b919e592-3f29-4a58-b7dc-8f722ed3e977" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_4e622113-856f-4a7e-8fb6-5f83cef3073b" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_b919e592-3f29-4a58-b7dc-8f722ed3e977" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/GOODWILLANDOTHERINTANGIBLEASSETSScheduleofChangesinCarryingAmountofGoodwillDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#GOODWILLANDOTHERINTANGIBLEASSETSScheduleofChangesinCarryingAmountofGoodwillDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/GOODWILLANDOTHERINTANGIBLEASSETSScheduleofChangesinCarryingAmountofGoodwillDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems_d85dadde-f502-49e5-b353-fa486e153c6e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_b157aa8c-1d9e-4e57-8a1c-9394edf8d06b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_d85dadde-f502-49e5-b353-fa486e153c6e" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_b157aa8c-1d9e-4e57-8a1c-9394edf8d06b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_1d4f7463-4b9a-4339-89f6-c1df4b1b7d64" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_b157aa8c-1d9e-4e57-8a1c-9394edf8d06b" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_1d4f7463-4b9a-4339-89f6-c1df4b1b7d64" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_1d4f7463-4b9a-4339-89f6-c1df4b1b7d64_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_1d4f7463-4b9a-4339-89f6-c1df4b1b7d64" xlink:to="loc_us-gaap_SegmentDomain_1d4f7463-4b9a-4339-89f6-c1df4b1b7d64_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_e6ee078c-a1df-4c5d-aadf-8d71728245eb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_1d4f7463-4b9a-4339-89f6-c1df4b1b7d64" xlink:to="loc_us-gaap_SegmentDomain_e6ee078c-a1df-4c5d-aadf-8d71728245eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CodmanSpecialtySurgicalMember_385653a6-83c2-4570-bfe3-a64562a11572" xlink:href="iart-20250930.xsd#iart_CodmanSpecialtySurgicalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e6ee078c-a1df-4c5d-aadf-8d71728245eb" xlink:to="loc_iart_CodmanSpecialtySurgicalMember_385653a6-83c2-4570-bfe3-a64562a11572" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_TissueTechnologiesMember_78a0205b-cd7d-4e3d-8346-65469bc33ac2" xlink:href="iart-20250930.xsd#iart_TissueTechnologiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e6ee078c-a1df-4c5d-aadf-8d71728245eb" xlink:to="loc_iart_TissueTechnologiesMember_78a0205b-cd7d-4e3d-8346-65469bc33ac2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_a7e205f8-5131-4bdb-88e2-10a867613b84" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_b157aa8c-1d9e-4e57-8a1c-9394edf8d06b" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_a7e205f8-5131-4bdb-88e2-10a867613b84" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_a7e205f8-5131-4bdb-88e2-10a867613b84_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_a7e205f8-5131-4bdb-88e2-10a867613b84" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_a7e205f8-5131-4bdb-88e2-10a867613b84_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_9db33a08-f60c-4b01-a01f-f472c635c787" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_a7e205f8-5131-4bdb-88e2-10a867613b84" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_9db33a08-f60c-4b01-a01f-f472c635c787" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_AcclarentInc.Member_c47e2045-0ae7-4371-9a1e-e6420f0fa933" xlink:href="iart-20250930.xsd#iart_AcclarentInc.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_9db33a08-f60c-4b01-a01f-f472c635c787" xlink:to="loc_iart_AcclarentInc.Member_c47e2045-0ae7-4371-9a1e-e6420f0fa933" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillRollForward_4cdd5a0b-cbea-461b-bd21-d8c4098c4b1f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_d85dadde-f502-49e5-b353-fa486e153c6e" xlink:to="loc_us-gaap_GoodwillRollForward_4cdd5a0b-cbea-461b-bd21-d8c4098c4b1f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_afecf425-396a-466b-9456-7c3a2fab0256" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_4cdd5a0b-cbea-461b-bd21-d8c4098c4b1f" xlink:to="loc_us-gaap_Goodwill_afecf425-396a-466b-9456-7c3a2fab0256" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_e96af311-22a9-4599-afb8-51cc0e659187" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_4cdd5a0b-cbea-461b-bd21-d8c4098c4b1f" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_e96af311-22a9-4599-afb8-51cc0e659187" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillForeignCurrencyTranslationGainLoss_cf23870f-b124-4b4a-8fce-1fa1d5957e6a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillForeignCurrencyTranslationGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_4cdd5a0b-cbea-461b-bd21-d8c4098c4b1f" xlink:to="loc_us-gaap_GoodwillForeignCurrencyTranslationGainLoss_cf23870f-b124-4b4a-8fce-1fa1d5957e6a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_d9ebf4d5-8eb6-4de9-9d25-457579123c3f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Goodwill"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/GOODWILLANDOTHERINTANGIBLEASSETSNarrativeDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#GOODWILLANDOTHERINTANGIBLEASSETSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/GOODWILLANDOTHERINTANGIBLEASSETSNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems_0fc27171-9a95-4190-9278-9fde0a9002d4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_da52ea94-3734-41e0-b6ab-519b34faa12d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_0fc27171-9a95-4190-9278-9fde0a9002d4" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_da52ea94-3734-41e0-b6ab-519b34faa12d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_8781f758-98d9-4d21-b2b3-893e0fc828ee" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_da52ea94-3734-41e0-b6ab-519b34faa12d" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_8781f758-98d9-4d21-b2b3-893e0fc828ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_8781f758-98d9-4d21-b2b3-893e0fc828ee_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_8781f758-98d9-4d21-b2b3-893e0fc828ee" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_8781f758-98d9-4d21-b2b3-893e0fc828ee_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_3a8ac24d-0092-47ce-90cb-f96f821f0cd2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_8781f758-98d9-4d21-b2b3-893e0fc828ee" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_3a8ac24d-0092-47ce-90cb-f96f821f0cd2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputLongTermRevenueGrowthRateMember_72ee1f3c-de79-42ca-9241-aedbb21975ec" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MeasurementInputLongTermRevenueGrowthRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_3a8ac24d-0092-47ce-90cb-f96f821f0cd2" xlink:to="loc_us-gaap_MeasurementInputLongTermRevenueGrowthRateMember_72ee1f3c-de79-42ca-9241-aedbb21975ec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputDiscountRateMember_e6fc3019-f053-48c6-9e3e-495d8bebac4b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MeasurementInputDiscountRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_3a8ac24d-0092-47ce-90cb-f96f821f0cd2" xlink:to="loc_us-gaap_MeasurementInputDiscountRateMember_e6fc3019-f053-48c6-9e3e-495d8bebac4b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportingUnitAxis_fd7445ea-6fda-41a1-83ab-a7d0b35e4bdc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReportingUnitAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_da52ea94-3734-41e0-b6ab-519b34faa12d" xlink:to="loc_us-gaap_ReportingUnitAxis_fd7445ea-6fda-41a1-83ab-a7d0b35e4bdc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportingUnitDomain_fd7445ea-6fda-41a1-83ab-a7d0b35e4bdc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReportingUnitDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReportingUnitAxis_fd7445ea-6fda-41a1-83ab-a7d0b35e4bdc" xlink:to="loc_us-gaap_ReportingUnitDomain_fd7445ea-6fda-41a1-83ab-a7d0b35e4bdc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportingUnitDomain_8b7a1894-3f89-4160-91f7-9e39a7152610" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReportingUnitDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReportingUnitAxis_fd7445ea-6fda-41a1-83ab-a7d0b35e4bdc" xlink:to="loc_us-gaap_ReportingUnitDomain_8b7a1894-3f89-4160-91f7-9e39a7152610" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_TissueTechnologiesMember_403dac96-0719-40b9-b757-a7811ea6bda7" xlink:href="iart-20250930.xsd#iart_TissueTechnologiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportingUnitDomain_8b7a1894-3f89-4160-91f7-9e39a7152610" xlink:to="loc_iart_TissueTechnologiesMember_403dac96-0719-40b9-b757-a7811ea6bda7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_NeurosurgeryMember_3afb40de-bfc1-48aa-b97e-389b6d93fbac" xlink:href="iart-20250930.xsd#iart_NeurosurgeryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportingUnitDomain_8b7a1894-3f89-4160-91f7-9e39a7152610" xlink:to="loc_iart_NeurosurgeryMember_3afb40de-bfc1-48aa-b97e-389b6d93fbac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_InstrumentsMember_09dad0c9-29fb-470e-a62f-bc794a9c0b01" xlink:href="iart-20250930.xsd#iart_InstrumentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReportingUnitDomain_8b7a1894-3f89-4160-91f7-9e39a7152610" xlink:to="loc_iart_InstrumentsMember_09dad0c9-29fb-470e-a62f-bc794a9c0b01" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueAxis_1673587e-5df7-4ad9-b0d5-8a0e8e65e193" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationTechniqueAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_da52ea94-3734-41e0-b6ab-519b34faa12d" xlink:to="loc_us-gaap_ValuationTechniqueAxis_1673587e-5df7-4ad9-b0d5-8a0e8e65e193" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_1673587e-5df7-4ad9-b0d5-8a0e8e65e193_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationTechniqueAxis_1673587e-5df7-4ad9-b0d5-8a0e8e65e193" xlink:to="loc_us-gaap_ValuationTechniqueDomain_1673587e-5df7-4ad9-b0d5-8a0e8e65e193_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_9720ec4d-6d46-4aab-b960-0719468cb5b9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationTechniqueDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationTechniqueAxis_1673587e-5df7-4ad9-b0d5-8a0e8e65e193" xlink:to="loc_us-gaap_ValuationTechniqueDomain_9720ec4d-6d46-4aab-b960-0719468cb5b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDiscountedCashFlowMember_30fc861d-618e-4b99-98df-b32fe27de583" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationTechniqueDiscountedCashFlowMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationTechniqueDomain_9720ec4d-6d46-4aab-b960-0719468cb5b9" xlink:to="loc_us-gaap_ValuationTechniqueDiscountedCashFlowMember_30fc861d-618e-4b99-98df-b32fe27de583" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_f5ce281b-dc3b-47d1-998b-ad1d5cdeb5a4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_da52ea94-3734-41e0-b6ab-519b34faa12d" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_f5ce281b-dc3b-47d1-998b-ad1d5cdeb5a4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_f5ce281b-dc3b-47d1-998b-ad1d5cdeb5a4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_f5ce281b-dc3b-47d1-998b-ad1d5cdeb5a4" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_f5ce281b-dc3b-47d1-998b-ad1d5cdeb5a4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_73dd3e63-4f24-421e-aa2d-6bc78276bf45" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_f5ce281b-dc3b-47d1-998b-ad1d5cdeb5a4" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_73dd3e63-4f24-421e-aa2d-6bc78276bf45" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeNamesMember_3d67c131-7e59-4723-a8ac-8c1d9cb7019d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_73dd3e63-4f24-421e-aa2d-6bc78276bf45" xlink:to="loc_us-gaap_TradeNamesMember_3d67c131-7e59-4723-a8ac-8c1d9cb7019d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_008f5cb1-a847-43bb-bcb5-90a5b69b0146" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_da52ea94-3734-41e0-b6ab-519b34faa12d" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_008f5cb1-a847-43bb-bcb5-90a5b69b0146" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_008f5cb1-a847-43bb-bcb5-90a5b69b0146_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_008f5cb1-a847-43bb-bcb5-90a5b69b0146" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_008f5cb1-a847-43bb-bcb5-90a5b69b0146_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_7f139b66-f8a4-4218-a78f-60a6cfc5508a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_008f5cb1-a847-43bb-bcb5-90a5b69b0146" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_7f139b66-f8a4-4218-a78f-60a6cfc5508a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CompletedTechnologyMember_a110c46d-3576-4ce7-9c2f-8432cb22018c" xlink:href="iart-20250930.xsd#iart_CompletedTechnologyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_7f139b66-f8a4-4218-a78f-60a6cfc5508a" xlink:to="loc_iart_CompletedTechnologyMember_a110c46d-3576-4ce7-9c2f-8432cb22018c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_b61b07f0-bc84-4da6-a47c-a193ca4433ad" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_7f139b66-f8a4-4218-a78f-60a6cfc5508a" xlink:to="loc_us-gaap_CustomerRelationshipsMember_b61b07f0-bc84-4da6-a47c-a193ca4433ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemAxis_4c6a0fdb-7a7d-40b5-b5f7-e07f24b737a2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_UnusualOrInfrequentItemAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_da52ea94-3734-41e0-b6ab-519b34faa12d" xlink:to="loc_us-gaap_UnusualOrInfrequentItemAxis_4c6a0fdb-7a7d-40b5-b5f7-e07f24b737a2" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemDomain_4c6a0fdb-7a7d-40b5-b5f7-e07f24b737a2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_UnusualOrInfrequentItemDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_UnusualOrInfrequentItemAxis_4c6a0fdb-7a7d-40b5-b5f7-e07f24b737a2" xlink:to="loc_us-gaap_UnusualOrInfrequentItemDomain_4c6a0fdb-7a7d-40b5-b5f7-e07f24b737a2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnusualOrInfrequentItemDomain_e484ce5c-50a1-4707-adf3-4e193e607c36" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_UnusualOrInfrequentItemDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_UnusualOrInfrequentItemAxis_4c6a0fdb-7a7d-40b5-b5f7-e07f24b737a2" xlink:to="loc_us-gaap_UnusualOrInfrequentItemDomain_e484ce5c-50a1-4707-adf3-4e193e607c36" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CompletedTechnologySurgiMendMember_f3d2c9de-46c9-40c8-886a-bdc0348aa99a" xlink:href="iart-20250930.xsd#iart_CompletedTechnologySurgiMendMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnusualOrInfrequentItemDomain_e484ce5c-50a1-4707-adf3-4e193e607c36" xlink:to="loc_iart_CompletedTechnologySurgiMendMember_f3d2c9de-46c9-40c8-886a-bdc0348aa99a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CompletedTechnologyPriMatrixMember_d91e4f50-6c12-465f-8834-744238149b8e" xlink:href="iart-20250930.xsd#iart_CompletedTechnologyPriMatrixMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnusualOrInfrequentItemDomain_e484ce5c-50a1-4707-adf3-4e193e607c36" xlink:to="loc_iart_CompletedTechnologyPriMatrixMember_d91e4f50-6c12-465f-8834-744238149b8e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_f2030e35-b4dc-4a05-856e-72ac3b65babf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_0fc27171-9a95-4190-9278-9fde0a9002d4" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_f2030e35-b4dc-4a05-856e-72ac3b65babf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_ReportingUnitMeasurementInput_81ce2664-f588-44fb-a8b3-4eba352031e4" xlink:href="iart-20250930.xsd#iart_ReportingUnitMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_0fc27171-9a95-4190-9278-9fde0a9002d4" xlink:to="loc_iart_ReportingUnitMeasurementInput_81ce2664-f588-44fb-a8b3-4eba352031e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_IndefiniteLivedIntangibleAssetsMeasurementInput_e4c03dae-c504-4ede-aca3-7e1e792c62d2" xlink:href="iart-20250930.xsd#iart_IndefiniteLivedIntangibleAssetsMeasurementInput"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_0fc27171-9a95-4190-9278-9fde0a9002d4" xlink:to="loc_iart_IndefiniteLivedIntangibleAssetsMeasurementInput_e4c03dae-c504-4ede-aca3-7e1e792c62d2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill_bb3af3d3-088a-41e4-aa68-194b31851341" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_0fc27171-9a95-4190-9278-9fde0a9002d4" xlink:to="loc_us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill_bb3af3d3-088a-41e4-aa68-194b31851341" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentForAmortization_fcf1cf7c-f870-4cad-87fe-d671593adf09" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdjustmentForAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_0fc27171-9a95-4190-9278-9fde0a9002d4" xlink:to="loc_us-gaap_AdjustmentForAmortization_fcf1cf7c-f870-4cad-87fe-d671593adf09" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSoldAmortization_589df202-2511-4078-8136-17c6f48d5263" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostOfGoodsAndServicesSoldAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_0fc27171-9a95-4190-9278-9fde0a9002d4" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSoldAmortization_589df202-2511-4078-8136-17c6f48d5263" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfIntangibleAssetsFinitelived_cdde5806-c85b-4d77-92ad-b30fb6dbc500" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ImpairmentOfIntangibleAssetsFinitelived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_0fc27171-9a95-4190-9278-9fde0a9002d4" xlink:to="loc_us-gaap_ImpairmentOfIntangibleAssetsFinitelived_cdde5806-c85b-4d77-92ad-b30fb6dbc500" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear_040fb682-8683-4b9b-b40b-ae9e024c6437" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_0fc27171-9a95-4190-9278-9fde0a9002d4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear_040fb682-8683-4b9b-b40b-ae9e024c6437" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_1d3b0e76-14af-4a8f-8ffc-9287c7569f85" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_0fc27171-9a95-4190-9278-9fde0a9002d4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_1d3b0e76-14af-4a8f-8ffc-9287c7569f85" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_b6012ab9-e809-4878-b9e0-5fff49eabb78" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_0fc27171-9a95-4190-9278-9fde0a9002d4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_b6012ab9-e809-4878-b9e0-5fff49eabb78" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_5d6692c8-9021-450b-a74d-b12f153d6aa0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_0fc27171-9a95-4190-9278-9fde0a9002d4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_5d6692c8-9021-450b-a74d-b12f153d6aa0" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_267e8571-726a-4f75-aacc-7359c11f7f5d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_0fc27171-9a95-4190-9278-9fde0a9002d4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_267e8571-726a-4f75-aacc-7359c11f7f5d" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_e72810a5-8f82-4840-91e4-da180f775aac" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_0fc27171-9a95-4190-9278-9fde0a9002d4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_e72810a5-8f82-4840-91e4-da180f775aac" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_427f61d1-fcde-417f-84dd-1e2c165da5cc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_0fc27171-9a95-4190-9278-9fde0a9002d4" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive_427f61d1-fcde-417f-84dd-1e2c165da5cc" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_3a2cbab2-7ac2-4274-95f5-0968c3096264" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_0fc27171-9a95-4190-9278-9fde0a9002d4" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_3a2cbab2-7ac2-4274-95f5-0968c3096264" xlink:type="arc" order="14"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/GOODWILLANDOTHERINTANGIBLEASSETSComponentsofCompanysIdentifiableIntangibleAssetsDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#GOODWILLANDOTHERINTANGIBLEASSETSComponentsofCompanysIdentifiableIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/GOODWILLANDOTHERINTANGIBLEASSETSComponentsofCompanysIdentifiableIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_ffcfe639-1b9e-4d6f-8288-e2c162e70884" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_60cee41f-47e2-4f22-b742-b26a6026cc06" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_ffcfe639-1b9e-4d6f-8288-e2c162e70884" xlink:to="loc_us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_60cee41f-47e2-4f22-b742-b26a6026cc06" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_17c4ed7b-4d06-463b-b643-77258642e69d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_60cee41f-47e2-4f22-b742-b26a6026cc06" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_17c4ed7b-4d06-463b-b643-77258642e69d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_17c4ed7b-4d06-463b-b643-77258642e69d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_17c4ed7b-4d06-463b-b643-77258642e69d" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_17c4ed7b-4d06-463b-b643-77258642e69d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_0ca3e316-342e-4e97-a418-639e8e7fd55c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_17c4ed7b-4d06-463b-b643-77258642e69d" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_0ca3e316-342e-4e97-a418-639e8e7fd55c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CompletedTechnologyMember_be92ad37-6358-42d4-9273-74b36a723f6f" xlink:href="iart-20250930.xsd#iart_CompletedTechnologyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_0ca3e316-342e-4e97-a418-639e8e7fd55c" xlink:to="loc_iart_CompletedTechnologyMember_be92ad37-6358-42d4-9273-74b36a723f6f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_38730e99-7b75-4bbe-b76a-084abae76b16" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_0ca3e316-342e-4e97-a418-639e8e7fd55c" xlink:to="loc_us-gaap_CustomerRelationshipsMember_38730e99-7b75-4bbe-b76a-084abae76b16" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_TrademarksBrandNamesMember_46c985b5-440e-490a-a4e4-a2791a8b4790" xlink:href="iart-20250930.xsd#iart_TrademarksBrandNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_0ca3e316-342e-4e97-a418-639e8e7fd55c" xlink:to="loc_iart_TrademarksBrandNamesMember_46c985b5-440e-490a-a4e4-a2791a8b4790" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_SupplierRelationShipsMember_8dfc8392-2e40-4114-bf40-233fb03d47c5" xlink:href="iart-20250930.xsd#iart_SupplierRelationShipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_0ca3e316-342e-4e97-a418-639e8e7fd55c" xlink:to="loc_iart_SupplierRelationShipsMember_8dfc8392-2e40-4114-bf40-233fb03d47c5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_AllOtherMember_bbcc6211-68ca-48fc-87b5-8c64ff9082d4" xlink:href="iart-20250930.xsd#iart_AllOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_0ca3e316-342e-4e97-a418-639e8e7fd55c" xlink:to="loc_iart_AllOtherMember_bbcc6211-68ca-48fc-87b5-8c64ff9082d4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_c1276fd2-944e-4e06-927c-64c7da53b22b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetByMajorClassTable_60cee41f-47e2-4f22-b742-b26a6026cc06" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_c1276fd2-944e-4e06-927c-64c7da53b22b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_c1276fd2-944e-4e06-927c-64c7da53b22b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_c1276fd2-944e-4e06-927c-64c7da53b22b" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_c1276fd2-944e-4e06-927c-64c7da53b22b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_746a1967-132e-4666-8a2b-668447fefeb0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_c1276fd2-944e-4e06-927c-64c7da53b22b" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_746a1967-132e-4666-8a2b-668447fefeb0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeNamesMember_7424a5f8-ca22-4e2f-b876-8de85d26fa6e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_746a1967-132e-4666-8a2b-668447fefeb0" xlink:to="loc_us-gaap_TradeNamesMember_7424a5f8-ca22-4e2f-b876-8de85d26fa6e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_a3b7b70e-4b82-4e10-84b3-60b99a49ff87" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_ffcfe639-1b9e-4d6f-8288-e2c162e70884" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_a3b7b70e-4b82-4e10-84b3-60b99a49ff87" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CostOfDefiniteAndIndefiniteLivedIntangibleAssetsGrossExcludingGoodwill_9d2859c3-49db-4577-9f6c-afbd8eef4327" xlink:href="iart-20250930.xsd#iart_CostOfDefiniteAndIndefiniteLivedIntangibleAssetsGrossExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_ffcfe639-1b9e-4d6f-8288-e2c162e70884" xlink:to="loc_iart_CostOfDefiniteAndIndefiniteLivedIntangibleAssetsGrossExcludingGoodwill_9d2859c3-49db-4577-9f6c-afbd8eef4327" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_9aa7fefb-9dda-4975-9af8-3adb616e1b8a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_ffcfe639-1b9e-4d6f-8288-e2c162e70884" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_9aa7fefb-9dda-4975-9af8-3adb616e1b8a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DefiniteAndIndefiniteLivedIntangibleAssetsNetExcludingGoodwill_c0880e7f-9266-4d66-bbd0-96501e80a81a" xlink:href="iart-20250930.xsd#iart_DefiniteAndIndefiniteLivedIntangibleAssetsNetExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsLineItems_ffcfe639-1b9e-4d6f-8288-e2c162e70884" xlink:to="loc_iart_DefiniteAndIndefiniteLivedIntangibleAssetsNetExcludingGoodwill_c0880e7f-9266-4d66-bbd0-96501e80a81a" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/DEBTMaximumTotalLeverageRatioTableDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#DEBTMaximumTotalLeverageRatioTableDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/DEBTMaximumTotalLeverageRatioTableDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_ab254b39-4081-46a4-8042-8909660435b2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_f33d4bba-a9fc-46e4-90a7-9fb06ebef863" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ab254b39-4081-46a4-8042-8909660435b2" xlink:to="loc_us-gaap_DebtInstrumentTable_f33d4bba-a9fc-46e4-90a7-9fb06ebef863" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DebtCovenantPeriodAxis_615f9151-b30f-40ac-8d67-5b30d1e2cc1d" xlink:href="iart-20250930.xsd#iart_DebtCovenantPeriodAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_f33d4bba-a9fc-46e4-90a7-9fb06ebef863" xlink:to="loc_iart_DebtCovenantPeriodAxis_615f9151-b30f-40ac-8d67-5b30d1e2cc1d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DebtCovenantPeriodDomain_615f9151-b30f-40ac-8d67-5b30d1e2cc1d_default" xlink:href="iart-20250930.xsd#iart_DebtCovenantPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_iart_DebtCovenantPeriodAxis_615f9151-b30f-40ac-8d67-5b30d1e2cc1d" xlink:to="loc_iart_DebtCovenantPeriodDomain_615f9151-b30f-40ac-8d67-5b30d1e2cc1d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DebtCovenantPeriodDomain_d332028f-4dc1-449c-ad3c-00f2ceda959d" xlink:href="iart-20250930.xsd#iart_DebtCovenantPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_iart_DebtCovenantPeriodAxis_615f9151-b30f-40ac-8d67-5b30d1e2cc1d" xlink:to="loc_iart_DebtCovenantPeriodDomain_d332028f-4dc1-449c-ad3c-00f2ceda959d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DebtCovenantPeriod1Member_cc72d941-b3ec-4459-8599-2fe0bd028bad" xlink:href="iart-20250930.xsd#iart_DebtCovenantPeriod1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iart_DebtCovenantPeriodDomain_d332028f-4dc1-449c-ad3c-00f2ceda959d" xlink:to="loc_iart_DebtCovenantPeriod1Member_cc72d941-b3ec-4459-8599-2fe0bd028bad" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DebtCovenantPeriod2Member_93df5131-5f02-41aa-bc72-83291a610b1d" xlink:href="iart-20250930.xsd#iart_DebtCovenantPeriod2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iart_DebtCovenantPeriodDomain_d332028f-4dc1-449c-ad3c-00f2ceda959d" xlink:to="loc_iart_DebtCovenantPeriod2Member_93df5131-5f02-41aa-bc72-83291a610b1d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DebtCovenantPeriod3Member_d6ebdebc-10af-4a3b-a2d3-5b5b4f8dbfc2" xlink:href="iart-20250930.xsd#iart_DebtCovenantPeriod3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iart_DebtCovenantPeriodDomain_d332028f-4dc1-449c-ad3c-00f2ceda959d" xlink:to="loc_iart_DebtCovenantPeriod3Member_d6ebdebc-10af-4a3b-a2d3-5b5b4f8dbfc2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DebtCovenantPeriod4Member_e120ea2c-521b-4b35-8b5f-1918ed72d717" xlink:href="iart-20250930.xsd#iart_DebtCovenantPeriod4Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iart_DebtCovenantPeriodDomain_d332028f-4dc1-449c-ad3c-00f2ceda959d" xlink:to="loc_iart_DebtCovenantPeriod4Member_e120ea2c-521b-4b35-8b5f-1918ed72d717" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_663cf8eb-1735-4aba-880a-ab91444c921f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_f33d4bba-a9fc-46e4-90a7-9fb06ebef863" xlink:to="loc_us-gaap_DebtInstrumentAxis_663cf8eb-1735-4aba-880a-ab91444c921f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_663cf8eb-1735-4aba-880a-ab91444c921f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_663cf8eb-1735-4aba-880a-ab91444c921f" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_663cf8eb-1735-4aba-880a-ab91444c921f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_3ed8fca8-0845-4ecf-80c2-219927509d1c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_663cf8eb-1735-4aba-880a-ab91444c921f" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_3ed8fca8-0845-4ecf-80c2-219927509d1c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_SeniorCreditFacilityMember_486d4bea-d720-4afd-93c3-0d617a387c35" xlink:href="iart-20250930.xsd#iart_SeniorCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_3ed8fca8-0845-4ecf-80c2-219927509d1c" xlink:to="loc_iart_SeniorCreditFacilityMember_486d4bea-d720-4afd-93c3-0d617a387c35" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DebtInstrumentCovenantMaximumLeverageRatio_e8042d59-eb6a-47aa-8556-59cda6ffa0b5" xlink:href="iart-20250930.xsd#iart_DebtInstrumentCovenantMaximumLeverageRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_ab254b39-4081-46a4-8042-8909660435b2" xlink:to="loc_iart_DebtInstrumentCovenantMaximumLeverageRatio_e8042d59-eb6a-47aa-8556-59cda6ffa0b5" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/DEBTNarrativeDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#DEBTNarrativeDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/DEBTNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_734a092c-4068-48e1-b5e1-df0efd28e461" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_us-gaap_DebtInstrumentTable_734a092c-4068-48e1-b5e1-df0efd28e461" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_1118d3f1-d27e-4ec1-b578-81c4dc67b9b9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_734a092c-4068-48e1-b5e1-df0efd28e461" xlink:to="loc_us-gaap_DebtInstrumentAxis_1118d3f1-d27e-4ec1-b578-81c4dc67b9b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_1118d3f1-d27e-4ec1-b578-81c4dc67b9b9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_1118d3f1-d27e-4ec1-b578-81c4dc67b9b9" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_1118d3f1-d27e-4ec1-b578-81c4dc67b9b9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_fc71ad8b-1766-458f-a89a-0102e2f11db5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_1118d3f1-d27e-4ec1-b578-81c4dc67b9b9" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_fc71ad8b-1766-458f-a89a-0102e2f11db5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_SeniorCreditFacilityMember_52f1d2ba-b987-458b-bb48-94bd6fb7b387" xlink:href="iart-20250930.xsd#iart_SeniorCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_fc71ad8b-1766-458f-a89a-0102e2f11db5" xlink:to="loc_iart_SeniorCreditFacilityMember_52f1d2ba-b987-458b-bb48-94bd6fb7b387" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_TermLoanFacilityMember_ba3d825f-169b-4479-9cd0-353c10c24621" xlink:href="iart-20250930.xsd#iart_TermLoanFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_fc71ad8b-1766-458f-a89a-0102e2f11db5" xlink:to="loc_iart_TermLoanFacilityMember_ba3d825f-169b-4479-9cd0-353c10c24621" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_TwoThousandTwentyFiveSeniorConvertibleNotesMember_948699d1-7b79-43a4-b9e2-694b7f4ab8b3" xlink:href="iart-20250930.xsd#iart_TwoThousandTwentyFiveSeniorConvertibleNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_fc71ad8b-1766-458f-a89a-0102e2f11db5" xlink:to="loc_iart_TwoThousandTwentyFiveSeniorConvertibleNotesMember_948699d1-7b79-43a4-b9e2-694b7f4ab8b3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_SecuritizationFacilityMember_b557e19e-86f1-443a-9481-b91bdf8c711a" xlink:href="iart-20250930.xsd#iart_SecuritizationFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_fc71ad8b-1766-458f-a89a-0102e2f11db5" xlink:to="loc_iart_SecuritizationFacilityMember_b557e19e-86f1-443a-9481-b91bdf8c711a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_fed0d386-50fc-431d-bf31-262439f81329" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_734a092c-4068-48e1-b5e1-df0efd28e461" xlink:to="loc_us-gaap_VariableRateAxis_fed0d386-50fc-431d-bf31-262439f81329" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_fed0d386-50fc-431d-bf31-262439f81329_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_fed0d386-50fc-431d-bf31-262439f81329" xlink:to="loc_us-gaap_VariableRateDomain_fed0d386-50fc-431d-bf31-262439f81329_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_fb021d4f-4254-4bc9-902f-e6ce45981068" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_fed0d386-50fc-431d-bf31-262439f81329" xlink:to="loc_us-gaap_VariableRateDomain_fb021d4f-4254-4bc9-902f-e6ce45981068" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_c6d735e7-5505-4a62-9c56-42c01501bd03" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuredOvernightFinancingRateSofrMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_fb021d4f-4254-4bc9-902f-e6ce45981068" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_c6d735e7-5505-4a62-9c56-42c01501bd03" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FederalFundsEffectiveSwapRateMember_e21536c9-45ee-4768-ba9a-b2437cbefa5b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FederalFundsEffectiveSwapRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_fb021d4f-4254-4bc9-902f-e6ce45981068" xlink:to="loc_us-gaap_FederalFundsEffectiveSwapRateMember_e21536c9-45ee-4768-ba9a-b2437cbefa5b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DebtCovenantPeriodAxis_7e5f2582-801b-43a5-b252-6d41a8c67ca9" xlink:href="iart-20250930.xsd#iart_DebtCovenantPeriodAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_734a092c-4068-48e1-b5e1-df0efd28e461" xlink:to="loc_iart_DebtCovenantPeriodAxis_7e5f2582-801b-43a5-b252-6d41a8c67ca9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DebtCovenantPeriodDomain_7e5f2582-801b-43a5-b252-6d41a8c67ca9_default" xlink:href="iart-20250930.xsd#iart_DebtCovenantPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_iart_DebtCovenantPeriodAxis_7e5f2582-801b-43a5-b252-6d41a8c67ca9" xlink:to="loc_iart_DebtCovenantPeriodDomain_7e5f2582-801b-43a5-b252-6d41a8c67ca9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DebtCovenantPeriodDomain_df83b53a-9f1f-4d49-94ba-fac43d9c93b0" xlink:href="iart-20250930.xsd#iart_DebtCovenantPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_iart_DebtCovenantPeriodAxis_7e5f2582-801b-43a5-b252-6d41a8c67ca9" xlink:to="loc_iart_DebtCovenantPeriodDomain_df83b53a-9f1f-4d49-94ba-fac43d9c93b0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CovenantReliefPeriodMember_98b8be31-14d1-4759-b38c-683447a4983f" xlink:href="iart-20250930.xsd#iart_CovenantReliefPeriodMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iart_DebtCovenantPeriodDomain_df83b53a-9f1f-4d49-94ba-fac43d9c93b0" xlink:to="loc_iart_CovenantReliefPeriodMember_98b8be31-14d1-4759-b38c-683447a4983f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_ThereafterCovenantReliefPeriodMember_23926a9e-90e1-43e0-aff3-18bdeb6e0897" xlink:href="iart-20250930.xsd#iart_ThereafterCovenantReliefPeriodMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_iart_DebtCovenantPeriodDomain_df83b53a-9f1f-4d49-94ba-fac43d9c93b0" xlink:to="loc_iart_ThereafterCovenantReliefPeriodMember_23926a9e-90e1-43e0-aff3-18bdeb6e0897" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_85148627-1dd2-48a0-b76a-d7082ca7a0d5" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_734a092c-4068-48e1-b5e1-df0efd28e461" xlink:to="loc_srt_RangeAxis_85148627-1dd2-48a0-b76a-d7082ca7a0d5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_85148627-1dd2-48a0-b76a-d7082ca7a0d5_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_85148627-1dd2-48a0-b76a-d7082ca7a0d5" xlink:to="loc_srt_RangeMember_85148627-1dd2-48a0-b76a-d7082ca7a0d5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_8445fbbd-563a-453e-b5b5-f64d66c3ad25" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_85148627-1dd2-48a0-b76a-d7082ca7a0d5" xlink:to="loc_srt_RangeMember_8445fbbd-563a-453e-b5b5-f64d66c3ad25" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_1040eeb2-9c72-4a66-96c1-2096dd9c25a2" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_8445fbbd-563a-453e-b5b5-f64d66c3ad25" xlink:to="loc_srt_MinimumMember_1040eeb2-9c72-4a66-96c1-2096dd9c25a2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_351f6c6a-497b-4780-b61d-4a999c029466" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_8445fbbd-563a-453e-b5b5-f64d66c3ad25" xlink:to="loc_srt_MaximumMember_351f6c6a-497b-4780-b61d-4a999c029466" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_f2136dd0-967c-4a53-953d-77e3a13a7f1f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_734a092c-4068-48e1-b5e1-df0efd28e461" xlink:to="loc_us-gaap_CreditFacilityAxis_f2136dd0-967c-4a53-953d-77e3a13a7f1f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_f2136dd0-967c-4a53-953d-77e3a13a7f1f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_f2136dd0-967c-4a53-953d-77e3a13a7f1f" xlink:to="loc_us-gaap_CreditFacilityDomain_f2136dd0-967c-4a53-953d-77e3a13a7f1f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_e83e279e-fc26-43a2-ae57-dd222270fadc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_f2136dd0-967c-4a53-953d-77e3a13a7f1f" xlink:to="loc_us-gaap_CreditFacilityDomain_e83e279e-fc26-43a2-ae57-dd222270fadc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_19aff3d6-149f-48a0-97df-95a0d8322c54" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_e83e279e-fc26-43a2-ae57-dd222270fadc" xlink:to="loc_us-gaap_SecuredDebtMember_19aff3d6-149f-48a0-97df-95a0d8322c54" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_5bc663eb-616f-47a5-ab6b-d373274324da" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_e83e279e-fc26-43a2-ae57-dd222270fadc" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_5bc663eb-616f-47a5-ab6b-d373274324da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StandbyLettersOfCreditMember_7b0b1629-5fdc-4971-850d-3845d7dfd413" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StandbyLettersOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_e83e279e-fc26-43a2-ae57-dd222270fadc" xlink:to="loc_us-gaap_StandbyLettersOfCreditMember_7b0b1629-5fdc-4971-850d-3845d7dfd413" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_SwinglineLoanMember_bcc32927-02c0-4d0c-b3b3-45f9b2d648f9" xlink:href="iart-20250930.xsd#iart_SwinglineLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_e83e279e-fc26-43a2-ae57-dd222270fadc" xlink:to="loc_iart_SwinglineLoanMember_bcc32927-02c0-4d0c-b3b3-45f9b2d648f9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_92a06fec-90ed-4e32-8021-6100ca4a6ef0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_734a092c-4068-48e1-b5e1-df0efd28e461" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_92a06fec-90ed-4e32-8021-6100ca4a6ef0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_92a06fec-90ed-4e32-8021-6100ca4a6ef0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_92a06fec-90ed-4e32-8021-6100ca4a6ef0" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_92a06fec-90ed-4e32-8021-6100ca4a6ef0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1c5901a0-bb99-4020-ba17-0a617ad3257e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_92a06fec-90ed-4e32-8021-6100ca4a6ef0" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1c5901a0-bb99-4020-ba17-0a617ad3257e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_13390455-0093-4223-bb1a-235291e57363" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1c5901a0-bb99-4020-ba17-0a617ad3257e" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_13390455-0093-4223-bb1a-235291e57363" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_c21c04db-28fc-4144-9fd4-1ac6c04146d9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_734a092c-4068-48e1-b5e1-df0efd28e461" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_c21c04db-28fc-4144-9fd4-1ac6c04146d9" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_c21c04db-28fc-4144-9fd4-1ac6c04146d9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_c21c04db-28fc-4144-9fd4-1ac6c04146d9" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_c21c04db-28fc-4144-9fd4-1ac6c04146d9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_2bb2dd3a-2b51-48f1-8739-561a537b6bb6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_c21c04db-28fc-4144-9fd4-1ac6c04146d9" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_2bb2dd3a-2b51-48f1-8739-561a537b6bb6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_63a26db9-f26a-4100-a1f5-52b2363264c2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_2bb2dd3a-2b51-48f1-8739-561a537b6bb6" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_63a26db9-f26a-4100-a1f5-52b2363264c2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_b2f83057-051f-4b2d-b15f-40070ea5f8cf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_63a26db9-f26a-4100-a1f5-52b2363264c2" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_b2f83057-051f-4b2d-b15f-40070ea5f8cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_6d7157af-14d0-450c-bb35-b5784cdaa0e5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_63a26db9-f26a-4100-a1f5-52b2363264c2" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_6d7157af-14d0-450c-bb35-b5784cdaa0e5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_ef81088f-1412-496a-828e-db9004c2c4e1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_734a092c-4068-48e1-b5e1-df0efd28e461" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_ef81088f-1412-496a-828e-db9004c2c4e1" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_ef81088f-1412-496a-828e-db9004c2c4e1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_ef81088f-1412-496a-828e-db9004c2c4e1" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_ef81088f-1412-496a-828e-db9004c2c4e1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_47566c75-d0aa-479d-80e5-108b13b5b7aa" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_ef81088f-1412-496a-828e-db9004c2c4e1" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_47566c75-d0aa-479d-80e5-108b13b5b7aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_4c1a0947-73ce-464e-a729-e5fb94d82f0b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_47566c75-d0aa-479d-80e5-108b13b5b7aa" xlink:to="loc_us-gaap_ConvertibleDebtMember_4c1a0947-73ce-464e-a729-e5fb94d82f0b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OptionIndexedToIssuersEquityEquityAxis_b96c3991-c0dc-4f05-addf-829dfb583cbf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OptionIndexedToIssuersEquityEquityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_734a092c-4068-48e1-b5e1-df0efd28e461" xlink:to="loc_us-gaap_OptionIndexedToIssuersEquityEquityAxis_b96c3991-c0dc-4f05-addf-829dfb583cbf" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OptionIndexedToIssuersEquityTypeDomain_b96c3991-c0dc-4f05-addf-829dfb583cbf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OptionIndexedToIssuersEquityTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OptionIndexedToIssuersEquityEquityAxis_b96c3991-c0dc-4f05-addf-829dfb583cbf" xlink:to="loc_us-gaap_OptionIndexedToIssuersEquityTypeDomain_b96c3991-c0dc-4f05-addf-829dfb583cbf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OptionIndexedToIssuersEquityTypeDomain_e1b2626f-5514-49ca-b810-d52cd781bfb1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OptionIndexedToIssuersEquityTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OptionIndexedToIssuersEquityEquityAxis_b96c3991-c0dc-4f05-addf-829dfb583cbf" xlink:to="loc_us-gaap_OptionIndexedToIssuersEquityTypeDomain_e1b2626f-5514-49ca-b810-d52cd781bfb1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CallOptionMember_2f5d87b7-689c-4e3f-bbf3-879855fe901c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CallOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OptionIndexedToIssuersEquityTypeDomain_e1b2626f-5514-49ca-b810-d52cd781bfb1" xlink:to="loc_us-gaap_CallOptionMember_2f5d87b7-689c-4e3f-bbf3-879855fe901c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DebtInstrumentBasisSpreadAdjustmentOnVariableRate_57d58798-b7b9-44a2-8456-eaa09e104408" xlink:href="iart-20250930.xsd#iart_DebtInstrumentBasisSpreadAdjustmentOnVariableRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_iart_DebtInstrumentBasisSpreadAdjustmentOnVariableRate_57d58798-b7b9-44a2-8456-eaa09e104408" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_0b4823e1-190c-4aa5-8d11-dd9a9beaeec5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_0b4823e1-190c-4aa5-8d11-dd9a9beaeec5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_baa46f10-80a9-4d2a-8f0e-9379b3efebc4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_baa46f10-80a9-4d2a-8f0e-9379b3efebc4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_8e15bb74-b18c-4254-96ba-0c58104f1bce" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_8e15bb74-b18c-4254-96ba-0c58104f1bce" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_af2b471b-b3d1-4027-b7b5-14a66e0a969a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_af2b471b-b3d1-4027-b7b5-14a66e0a969a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DebtInstrumentGrossFairValueDisclosure_1f2dcb37-5cc3-4d4b-9d16-80edb3bfb79c" xlink:href="iart-20250930.xsd#iart_DebtInstrumentGrossFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_iart_DebtInstrumentGrossFairValueDisclosure_1f2dcb37-5cc3-4d4b-9d16-80edb3bfb79c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtWeightedAverageInterestRate_749dc16b-d2e1-4f97-b9f0-e0c99d8015c3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtWeightedAverageInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_us-gaap_DebtWeightedAverageInterestRate_749dc16b-d2e1-4f97-b9f0-e0c99d8015c3" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtCurrent_7c49ad71-518e-460d-a88b-b9d1e4c41842" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuredDebtCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_us-gaap_SecuredDebtCurrent_7c49ad71-518e-460d-a88b-b9d1e4c41842" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_4e96ddde-eb38-477e-bf71-59db929064e0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_4e96ddde-eb38-477e-bf71-59db929064e0" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_d308552d-0473-4487-98ad-a7a364b2de0f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_us-gaap_LineOfCredit_d308552d-0473-4487-98ad-a7a364b2de0f" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_InterestPaymentsReminderOfFiscalYear_ae988dd5-ce44-4918-add4-4a01ba181512" xlink:href="iart-20250930.xsd#iart_InterestPaymentsReminderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_iart_InterestPaymentsReminderOfFiscalYear_ae988dd5-ce44-4918-add4-4a01ba181512" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_InterestPaymentsYearOne_73dd7021-1d7c-4f40-90da-1f82c7bd7dc4" xlink:href="iart-20250930.xsd#iart_InterestPaymentsYearOne"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_iart_InterestPaymentsYearOne_73dd7021-1d7c-4f40-90da-1f82c7bd7dc4" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_InterestPaymentsYearTwo_c4e3bc90-858f-4273-8af7-f139a6ee05fc" xlink:href="iart-20250930.xsd#iart_InterestPaymentsYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_iart_InterestPaymentsYearTwo_c4e3bc90-858f-4273-8af7-f139a6ee05fc" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_InterestPaymentsYearThree_823fdf7f-8685-4c2d-b3fc-647ed137d086" xlink:href="iart-20250930.xsd#iart_InterestPaymentsYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_iart_InterestPaymentsYearThree_823fdf7f-8685-4c2d-b3fc-647ed137d086" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_2c9c0f5b-0514-471c-b021-5eb80c38f52a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_2c9c0f5b-0514-471c-b021-5eb80c38f52a" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfConvertibleDebt_778c26a8-a5c8-47cb-b5f1-d597ac83eb87" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RepaymentsOfConvertibleDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_us-gaap_RepaymentsOfConvertibleDebt_778c26a8-a5c8-47cb-b5f1-d597ac83eb87" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtConversionConvertedInstrumentSharesIssued1_55f80983-b649-4b28-8e69-0f73921bb90f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtConversionConvertedInstrumentSharesIssued1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_us-gaap_DebtConversionConvertedInstrumentSharesIssued1_55f80983-b649-4b28-8e69-0f73921bb90f" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_PaymentsForOptionIndexToIssuersEquity_c7d4e2da-9c0b-4618-b4dc-8da65d7c6bb0" xlink:href="iart-20250930.xsd#iart_PaymentsForOptionIndexToIssuersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_iart_PaymentsForOptionIndexToIssuersEquity_c7d4e2da-9c0b-4618-b4dc-8da65d7c6bb0" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfWarrants_9ffb28b7-8f47-4f2c-ac77-72adea20577b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromIssuanceOfWarrants"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfWarrants_9ffb28b7-8f47-4f2c-ac77-72adea20577b" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_ee0f39f7-5ee0-426d-bca9-e6272fc2412c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentConvertibleConversionPrice1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_ee0f39f7-5ee0-426d-bca9-e6272fc2412c" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_5b4c1494-92ed-4bc2-a220-fbdbfd765eb3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_5b4c1494-92ed-4bc2-a220-fbdbfd765eb3" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_TransferorsInterestsInTransferredFinancialAssetsMaximumInvestmentLimit_c6734d90-2585-4409-bf18-e20270ae536c" xlink:href="iart-20250930.xsd#iart_TransferorsInterestsInTransferredFinancialAssetsMaximumInvestmentLimit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_iart_TransferorsInterestsInTransferredFinancialAssetsMaximumInvestmentLimit_c6734d90-2585-4409-bf18-e20270ae536c" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_TransferorsInterestsInTransferredFinancialAssetsIssuanceCosts_079b682f-f7cc-4b56-80cc-e354bbb3e1a4" xlink:href="iart-20250930.xsd#iart_TransferorsInterestsInTransferredFinancialAssetsIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_iart_TransferorsInterestsInTransferredFinancialAssetsIssuanceCosts_079b682f-f7cc-4b56-80cc-e354bbb3e1a4" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DebtInstrumentSecuritizationFacilityAgreementTerm_9afab2ed-54c3-4bb4-b90a-df65a8cc222e" xlink:href="iart-20250930.xsd#iart_DebtInstrumentSecuritizationFacilityAgreementTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_iart_DebtInstrumentSecuritizationFacilityAgreementTerm_9afab2ed-54c3-4bb4-b90a-df65a8cc222e" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_TransferorsInterestsInTransferredFinancialAssetsUnamortizedIssuanceCosts_fcdd4f5e-f96c-4e87-9ed8-9884b5b824ae" xlink:href="iart-20250930.xsd#iart_TransferorsInterestsInTransferredFinancialAssetsUnamortizedIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_iart_TransferorsInterestsInTransferredFinancialAssetsUnamortizedIssuanceCosts_fcdd4f5e-f96c-4e87-9ed8-9884b5b824ae" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DebtWeightedAverageInterestRateFromSecuritization_d57279fa-f403-44b9-bbc4-457c7bb9b7aa" xlink:href="iart-20250930.xsd#iart_DebtWeightedAverageInterestRateFromSecuritization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b433c0e8-7f07-4a4e-911a-bb5c238a83f2" xlink:to="loc_iart_DebtWeightedAverageInterestRateFromSecuritization_d57279fa-f403-44b9-bbc4-457c7bb9b7aa" xlink:type="arc" order="25"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/DEBTScheduleofCarryingAmountsandEstimatedFairValuesofDebtInstrumentsDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#DEBTScheduleofCarryingAmountsandEstimatedFairValuesofDebtInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/DEBTScheduleofCarryingAmountsandEstimatedFairValuesofDebtInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_2a8cb8f7-c5a8-4bb9-8e89-0e68b710eff1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_45ee36b3-6d2d-4c39-9117-3ccc717ece12" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_2a8cb8f7-c5a8-4bb9-8e89-0e68b710eff1" xlink:to="loc_us-gaap_DebtInstrumentTable_45ee36b3-6d2d-4c39-9117-3ccc717ece12" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_c3eda954-0ce6-40f5-b2ec-f7f496e88c04" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_45ee36b3-6d2d-4c39-9117-3ccc717ece12" xlink:to="loc_us-gaap_CreditFacilityAxis_c3eda954-0ce6-40f5-b2ec-f7f496e88c04" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_c3eda954-0ce6-40f5-b2ec-f7f496e88c04_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_c3eda954-0ce6-40f5-b2ec-f7f496e88c04" xlink:to="loc_us-gaap_CreditFacilityDomain_c3eda954-0ce6-40f5-b2ec-f7f496e88c04_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_28be1afb-0e4d-4937-8483-20248f8b12ce" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_c3eda954-0ce6-40f5-b2ec-f7f496e88c04" xlink:to="loc_us-gaap_CreditFacilityDomain_28be1afb-0e4d-4937-8483-20248f8b12ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_7d1f9df5-0a27-4b0c-a615-f292963b4c37" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_28be1afb-0e4d-4937-8483-20248f8b12ce" xlink:to="loc_us-gaap_SecuredDebtMember_7d1f9df5-0a27-4b0c-a615-f292963b4c37" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_64f4a143-d429-4f7b-bc65-4c087e203772" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_28be1afb-0e4d-4937-8483-20248f8b12ce" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_64f4a143-d429-4f7b-bc65-4c087e203772" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_2f49b7c7-69ca-41c7-bfec-2c5860986e98" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_45ee36b3-6d2d-4c39-9117-3ccc717ece12" xlink:to="loc_us-gaap_DebtInstrumentAxis_2f49b7c7-69ca-41c7-bfec-2c5860986e98" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_2f49b7c7-69ca-41c7-bfec-2c5860986e98_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_2f49b7c7-69ca-41c7-bfec-2c5860986e98" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_2f49b7c7-69ca-41c7-bfec-2c5860986e98_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_38bf364e-1294-4055-b222-952add73a2c0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_2f49b7c7-69ca-41c7-bfec-2c5860986e98" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_38bf364e-1294-4055-b222-952add73a2c0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_TermLoanFacilityMember_e38722f4-6d03-4cf3-a797-6bf00635df41" xlink:href="iart-20250930.xsd#iart_TermLoanFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_38bf364e-1294-4055-b222-952add73a2c0" xlink:to="loc_iart_TermLoanFacilityMember_e38722f4-6d03-4cf3-a797-6bf00635df41" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_SeniorCreditFacilityMember_dbf0020b-4eff-42d5-92d4-c851fe9014b3" xlink:href="iart-20250930.xsd#iart_SeniorCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_38bf364e-1294-4055-b222-952add73a2c0" xlink:to="loc_iart_SeniorCreditFacilityMember_dbf0020b-4eff-42d5-92d4-c851fe9014b3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_TwoThousandTwentyFiveSeniorConvertibleNotesMember_f609bb9e-0e4c-4b69-92b9-8f5bd049072a" xlink:href="iart-20250930.xsd#iart_TwoThousandTwentyFiveSeniorConvertibleNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_38bf364e-1294-4055-b222-952add73a2c0" xlink:to="loc_iart_TwoThousandTwentyFiveSeniorConvertibleNotesMember_f609bb9e-0e4c-4b69-92b9-8f5bd049072a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_SecuritizationFacilityMember_9ae699bd-7357-4ee4-8954-890a3e2cdc9b" xlink:href="iart-20250930.xsd#iart_SecuritizationFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_38bf364e-1294-4055-b222-952add73a2c0" xlink:to="loc_iart_SecuritizationFacilityMember_9ae699bd-7357-4ee4-8954-890a3e2cdc9b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_ac8bc9e5-5739-4df4-9c87-963db76df53a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_45ee36b3-6d2d-4c39-9117-3ccc717ece12" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_ac8bc9e5-5739-4df4-9c87-963db76df53a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_ac8bc9e5-5739-4df4-9c87-963db76df53a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_ac8bc9e5-5739-4df4-9c87-963db76df53a" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_ac8bc9e5-5739-4df4-9c87-963db76df53a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_24c08f1a-3d98-43a1-942f-fde26c909eb8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_ac8bc9e5-5739-4df4-9c87-963db76df53a" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_24c08f1a-3d98-43a1-942f-fde26c909eb8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_4539844c-607e-4ff2-9b69-4c4c4b05c34f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_24c08f1a-3d98-43a1-942f-fde26c909eb8" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_4539844c-607e-4ff2-9b69-4c4c4b05c34f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_59bedda5-6174-4642-aa4e-0ad583a7565a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_24c08f1a-3d98-43a1-942f-fde26c909eb8" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_59bedda5-6174-4642-aa4e-0ad583a7565a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_a6c10ed9-b223-4f30-b6c9-06fda46c89f1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_45ee36b3-6d2d-4c39-9117-3ccc717ece12" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_a6c10ed9-b223-4f30-b6c9-06fda46c89f1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_a6c10ed9-b223-4f30-b6c9-06fda46c89f1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_a6c10ed9-b223-4f30-b6c9-06fda46c89f1" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_a6c10ed9-b223-4f30-b6c9-06fda46c89f1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_8c0cb5b9-fcb9-4c94-a2e7-21b95e219119" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_a6c10ed9-b223-4f30-b6c9-06fda46c89f1" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_8c0cb5b9-fcb9-4c94-a2e7-21b95e219119" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_f5a146be-7ab2-4e0b-900d-18c9268c082e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_8c0cb5b9-fcb9-4c94-a2e7-21b95e219119" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_f5a146be-7ab2-4e0b-900d-18c9268c082e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_155b807b-009f-4180-8a18-c3d591a8e870" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_f5a146be-7ab2-4e0b-900d-18c9268c082e" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_155b807b-009f-4180-8a18-c3d591a8e870" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_2d04450b-0e94-4c63-b0f1-47fa5fef76fe" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_f5a146be-7ab2-4e0b-900d-18c9268c082e" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_2d04450b-0e94-4c63-b0f1-47fa5fef76fe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_e22b12b3-2f86-48c2-9f4e-74f5fcd3b563" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_45ee36b3-6d2d-4c39-9117-3ccc717ece12" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_e22b12b3-2f86-48c2-9f4e-74f5fcd3b563" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_e22b12b3-2f86-48c2-9f4e-74f5fcd3b563_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_e22b12b3-2f86-48c2-9f4e-74f5fcd3b563" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_e22b12b3-2f86-48c2-9f4e-74f5fcd3b563_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_d272dc5b-184b-455c-94b7-1c8daf4abeeb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_e22b12b3-2f86-48c2-9f4e-74f5fcd3b563" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_d272dc5b-184b-455c-94b7-1c8daf4abeeb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_522485e6-0cbc-499c-a19f-b618b1c3d2aa" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_d272dc5b-184b-455c-94b7-1c8daf4abeeb" xlink:to="loc_us-gaap_ConvertibleDebtMember_522485e6-0cbc-499c-a19f-b618b1c3d2aa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DebtInstrumentGrossFairValueDisclosure_a2517de7-6d23-4934-bd54-ca925691da89" xlink:href="iart-20250930.xsd#iart_DebtInstrumentGrossFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_2a8cb8f7-c5a8-4bb9-8e89-0e68b710eff1" xlink:to="loc_iart_DebtInstrumentGrossFairValueDisclosure_a2517de7-6d23-4934-bd54-ca925691da89" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_e800a74d-ebb9-489a-921e-ea79e1ba398c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_2a8cb8f7-c5a8-4bb9-8e89-0e68b710eff1" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_e800a74d-ebb9-489a-921e-ea79e1ba398c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFairValue_16a96d77-b0c9-4c82-84eb-c49922e34a01" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_2a8cb8f7-c5a8-4bb9-8e89-0e68b710eff1" xlink:to="loc_us-gaap_DebtInstrumentFairValue_16a96d77-b0c9-4c82-84eb-c49922e34a01" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/DERIVATIVEINSTRUMENTSScheduleofDerivativeInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_d533761f-9fa1-4d17-86b8-71a49524c41c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_7ac55aaf-c353-42e7-b093-e505d45f0dc1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_d533761f-9fa1-4d17-86b8-71a49524c41c" xlink:to="loc_us-gaap_DerivativeTable_7ac55aaf-c353-42e7-b093-e505d45f0dc1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_8d9b69d5-ac4e-43a3-877b-8e49d19fd50a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_7ac55aaf-c353-42e7-b093-e505d45f0dc1" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_8d9b69d5-ac4e-43a3-877b-8e49d19fd50a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_8d9b69d5-ac4e-43a3-877b-8e49d19fd50a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_8d9b69d5-ac4e-43a3-877b-8e49d19fd50a" xlink:to="loc_us-gaap_HedgingRelationshipDomain_8d9b69d5-ac4e-43a3-877b-8e49d19fd50a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_e02d10e8-559b-480a-8eb2-17fee6385018" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_8d9b69d5-ac4e-43a3-877b-8e49d19fd50a" xlink:to="loc_us-gaap_HedgingRelationshipDomain_e02d10e8-559b-480a-8eb2-17fee6385018" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_a62f990b-7fe3-4533-be27-74aa1525257f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashFlowHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_e02d10e8-559b-480a-8eb2-17fee6385018" xlink:to="loc_us-gaap_CashFlowHedgingMember_a62f990b-7fe3-4533-be27-74aa1525257f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_dc42c092-58cf-4cc9-a1fb-9ba252159a97" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_7ac55aaf-c353-42e7-b093-e505d45f0dc1" xlink:to="loc_us-gaap_HedgingDesignationAxis_dc42c092-58cf-4cc9-a1fb-9ba252159a97" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_dc42c092-58cf-4cc9-a1fb-9ba252159a97_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_dc42c092-58cf-4cc9-a1fb-9ba252159a97" xlink:to="loc_us-gaap_HedgingDesignationDomain_dc42c092-58cf-4cc9-a1fb-9ba252159a97_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_1a20360f-8e65-4a81-b213-b5ba4dfe0b44" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_dc42c092-58cf-4cc9-a1fb-9ba252159a97" xlink:to="loc_us-gaap_HedgingDesignationDomain_1a20360f-8e65-4a81-b213-b5ba4dfe0b44" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_f30a661b-d06a-4781-8a64-dbd585e47ae7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_1a20360f-8e65-4a81-b213-b5ba4dfe0b44" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_f30a661b-d06a-4781-8a64-dbd585e47ae7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_005a5a16-7443-48b9-9fe7-0d513c927d7d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_7ac55aaf-c353-42e7-b093-e505d45f0dc1" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_005a5a16-7443-48b9-9fe7-0d513c927d7d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_005a5a16-7443-48b9-9fe7-0d513c927d7d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_005a5a16-7443-48b9-9fe7-0d513c927d7d" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_005a5a16-7443-48b9-9fe7-0d513c927d7d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_c4305715-f742-4c4c-b35e-bc178b7bd936" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_005a5a16-7443-48b9-9fe7-0d513c927d7d" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_c4305715-f742-4c4c-b35e-bc178b7bd936" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_InterestRateSwapDesignatedOctober102018Tranche1Member_f1df530d-fc2f-4f13-a693-e5227cdfcf7d" xlink:href="iart-20250930.xsd#iart_InterestRateSwapDesignatedOctober102018Tranche1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c4305715-f742-4c4c-b35e-bc178b7bd936" xlink:to="loc_iart_InterestRateSwapDesignatedOctober102018Tranche1Member_f1df530d-fc2f-4f13-a693-e5227cdfcf7d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_InterestRateSwapDesignatedOctober102018Tranche2Member_0670c7de-dd65-4e28-8f3d-90d132852826" xlink:href="iart-20250930.xsd#iart_InterestRateSwapDesignatedOctober102018Tranche2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c4305715-f742-4c4c-b35e-bc178b7bd936" xlink:to="loc_iart_InterestRateSwapDesignatedOctober102018Tranche2Member_0670c7de-dd65-4e28-8f3d-90d132852826" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_InterestRateSwapDesignatedOctober102018Tranche3Member_c8b75160-dd02-4704-af26-4b1a2f5c14f7" xlink:href="iart-20250930.xsd#iart_InterestRateSwapDesignatedOctober102018Tranche3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c4305715-f742-4c4c-b35e-bc178b7bd936" xlink:to="loc_iart_InterestRateSwapDesignatedOctober102018Tranche3Member_c8b75160-dd02-4704-af26-4b1a2f5c14f7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_InterestRateSwapDesignatedDecember182018Tranche1Member_a07c0345-23c4-47e8-8dd6-c37e2e113ef7" xlink:href="iart-20250930.xsd#iart_InterestRateSwapDesignatedDecember182018Tranche1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c4305715-f742-4c4c-b35e-bc178b7bd936" xlink:to="loc_iart_InterestRateSwapDesignatedDecember182018Tranche1Member_a07c0345-23c4-47e8-8dd6-c37e2e113ef7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_InterestRateSwapDesignatedDecember182018Tranche2Member_b39c3689-25d2-40de-be20-d112a92f2bef" xlink:href="iart-20250930.xsd#iart_InterestRateSwapDesignatedDecember182018Tranche2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c4305715-f742-4c4c-b35e-bc178b7bd936" xlink:to="loc_iart_InterestRateSwapDesignatedDecember182018Tranche2Member_b39c3689-25d2-40de-be20-d112a92f2bef" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_InterestRateSwapDesignatedDecember152020Tranche1Member_da388d26-0d99-4188-bf6e-394904461320" xlink:href="iart-20250930.xsd#iart_InterestRateSwapDesignatedDecember152020Tranche1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c4305715-f742-4c4c-b35e-bc178b7bd936" xlink:to="loc_iart_InterestRateSwapDesignatedDecember152020Tranche1Member_da388d26-0d99-4188-bf6e-394904461320" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_InterestRateSwapDesignatedDecember152020Tranche2Member_2df388bf-375c-4f0e-a2cf-8fce86db5893" xlink:href="iart-20250930.xsd#iart_InterestRateSwapDesignatedDecember152020Tranche2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c4305715-f742-4c4c-b35e-bc178b7bd936" xlink:to="loc_iart_InterestRateSwapDesignatedDecember152020Tranche2Member_2df388bf-375c-4f0e-a2cf-8fce86db5893" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_InterestRateSwapDesignatedMarch312023Member_817bf1d3-68fb-4f44-9ea6-441c91f7cf5b" xlink:href="iart-20250930.xsd#iart_InterestRateSwapDesignatedMarch312023Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c4305715-f742-4c4c-b35e-bc178b7bd936" xlink:to="loc_iart_InterestRateSwapDesignatedMarch312023Member_817bf1d3-68fb-4f44-9ea6-441c91f7cf5b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_15994b5d-4693-40ca-8ac6-dbfa460af9de" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_d533761f-9fa1-4d17-86b8-71a49524c41c" xlink:to="loc_us-gaap_DerivativeNotionalAmount_15994b5d-4693-40ca-8ac6-dbfa460af9de" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFixedInterestRate_49294e02-c7f3-4cb2-8a98-3fb209dcdc05" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeFixedInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_d533761f-9fa1-4d17-86b8-71a49524c41c" xlink:to="loc_us-gaap_DerivativeFixedInterestRate_49294e02-c7f3-4cb2-8a98-3fb209dcdc05" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeNet_76be7186-ca9f-451c-9be7-1b8a7251e304" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeFairValueOfDerivativeNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_d533761f-9fa1-4d17-86b8-71a49524c41c" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeNet_76be7186-ca9f-451c-9be7-1b8a7251e304" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/DERIVATIVEINSTRUMENTSNarrativeDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#DERIVATIVEINSTRUMENTSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/DERIVATIVEINSTRUMENTSNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_84e3962a-6c30-4b5c-a883-f2dbca705ab0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_022c60a9-de71-49bd-b05b-aaf31040dbee" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_84e3962a-6c30-4b5c-a883-f2dbca705ab0" xlink:to="loc_us-gaap_DerivativeTable_022c60a9-de71-49bd-b05b-aaf31040dbee" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_ee57a6d1-27d4-4448-9a1c-c37f2ff4866d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_022c60a9-de71-49bd-b05b-aaf31040dbee" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_ee57a6d1-27d4-4448-9a1c-c37f2ff4866d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_ee57a6d1-27d4-4448-9a1c-c37f2ff4866d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_ee57a6d1-27d4-4448-9a1c-c37f2ff4866d" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_ee57a6d1-27d4-4448-9a1c-c37f2ff4866d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_fa3f369e-f02f-4970-98eb-437e8223f7aa" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_ee57a6d1-27d4-4448-9a1c-c37f2ff4866d" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_fa3f369e-f02f-4970-98eb-437e8223f7aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_04709b94-1b65-4941-be97-433a6d29f94a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_fa3f369e-f02f-4970-98eb-437e8223f7aa" xlink:to="loc_us-gaap_InterestRateSwapMember_04709b94-1b65-4941-be97-433a6d29f94a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CrossCurrencyInterestRateContractMember_74fc23c1-47c6-41a6-90ac-c708b2e7ceec" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CrossCurrencyInterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_fa3f369e-f02f-4970-98eb-437e8223f7aa" xlink:to="loc_us-gaap_CrossCurrencyInterestRateContractMember_74fc23c1-47c6-41a6-90ac-c708b2e7ceec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrencySwapMember_001eccda-3772-40a5-baa4-c68163c20abe" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CurrencySwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_fa3f369e-f02f-4970-98eb-437e8223f7aa" xlink:to="loc_us-gaap_CurrencySwapMember_001eccda-3772-40a5-baa4-c68163c20abe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeForwardMember_e84d6b5f-8370-43fe-a07b-0d688e095540" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignExchangeForwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_fa3f369e-f02f-4970-98eb-437e8223f7aa" xlink:to="loc_us-gaap_ForeignExchangeForwardMember_e84d6b5f-8370-43fe-a07b-0d688e095540" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CNHExchangeForwardMember_d8eb93fa-1a2a-4e08-9331-9dbcadc07935" xlink:href="iart-20250930.xsd#iart_CNHExchangeForwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_fa3f369e-f02f-4970-98eb-437e8223f7aa" xlink:to="loc_iart_CNHExchangeForwardMember_d8eb93fa-1a2a-4e08-9331-9dbcadc07935" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_EURExchangeForwardMember_12cc81ee-a5b6-4a0a-8198-78b7e209f50e" xlink:href="iart-20250930.xsd#iart_EURExchangeForwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_fa3f369e-f02f-4970-98eb-437e8223f7aa" xlink:to="loc_iart_EURExchangeForwardMember_12cc81ee-a5b6-4a0a-8198-78b7e209f50e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_056dc20e-b7d2-4b71-8b90-d2655dda8438" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_022c60a9-de71-49bd-b05b-aaf31040dbee" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_056dc20e-b7d2-4b71-8b90-d2655dda8438" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_056dc20e-b7d2-4b71-8b90-d2655dda8438_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_056dc20e-b7d2-4b71-8b90-d2655dda8438" xlink:to="loc_us-gaap_HedgingRelationshipDomain_056dc20e-b7d2-4b71-8b90-d2655dda8438_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_151e140c-cf86-4492-9f15-9bbc1682917a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_056dc20e-b7d2-4b71-8b90-d2655dda8438" xlink:to="loc_us-gaap_HedgingRelationshipDomain_151e140c-cf86-4492-9f15-9bbc1682917a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_a9d36ab6-a901-49e2-ac5f-ab456f3531b4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashFlowHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_151e140c-cf86-4492-9f15-9bbc1682917a" xlink:to="loc_us-gaap_CashFlowHedgingMember_a9d36ab6-a901-49e2-ac5f-ab456f3531b4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetInvestmentHedgingMember_b754da13-9d21-4f27-b377-fef4a72ad79d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetInvestmentHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_151e140c-cf86-4492-9f15-9bbc1682917a" xlink:to="loc_us-gaap_NetInvestmentHedgingMember_b754da13-9d21-4f27-b377-fef4a72ad79d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_9209b681-7efa-432d-aec9-609156b22d1f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_022c60a9-de71-49bd-b05b-aaf31040dbee" xlink:to="loc_us-gaap_HedgingDesignationAxis_9209b681-7efa-432d-aec9-609156b22d1f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_9209b681-7efa-432d-aec9-609156b22d1f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_9209b681-7efa-432d-aec9-609156b22d1f" xlink:to="loc_us-gaap_HedgingDesignationDomain_9209b681-7efa-432d-aec9-609156b22d1f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_f7500cea-0a52-4709-9dbd-200a140d3f3d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_9209b681-7efa-432d-aec9-609156b22d1f" xlink:to="loc_us-gaap_HedgingDesignationDomain_f7500cea-0a52-4709-9dbd-200a140d3f3d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_8f4c86cf-f240-4d4a-9a41-04576637ee16" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_f7500cea-0a52-4709-9dbd-200a140d3f3d" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_8f4c86cf-f240-4d4a-9a41-04576637ee16" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_adcbf540-d6ed-4e50-9813-55d430193088" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_f7500cea-0a52-4709-9dbd-200a140d3f3d" xlink:to="loc_us-gaap_NondesignatedMember_adcbf540-d6ed-4e50-9813-55d430193088" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_d2c08e91-20e3-4852-a6c9-9dcd8999251c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_022c60a9-de71-49bd-b05b-aaf31040dbee" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_d2c08e91-20e3-4852-a6c9-9dcd8999251c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_d2c08e91-20e3-4852-a6c9-9dcd8999251c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_d2c08e91-20e3-4852-a6c9-9dcd8999251c" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_d2c08e91-20e3-4852-a6c9-9dcd8999251c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_3b7cca2c-7a5e-4c22-b971-e9e112a5a04b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_d2c08e91-20e3-4852-a6c9-9dcd8999251c" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_3b7cca2c-7a5e-4c22-b971-e9e112a5a04b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpenseMember_e89e8b7d-1606-4c80-bcce-3012cc9da683" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherNonoperatingIncomeExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_3b7cca2c-7a5e-4c22-b971-e9e112a5a04b" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpenseMember_e89e8b7d-1606-4c80-bcce-3012cc9da683" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeMember_29d18f27-68e3-4ca1-b014-ae9cf67f8df5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_3b7cca2c-7a5e-4c22-b971-e9e112a5a04b" xlink:to="loc_us-gaap_InterestIncomeMember_29d18f27-68e3-4ca1-b014-ae9cf67f8df5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfSalesMember_e2b3984e-5596-4e8c-b11c-121f0c013170" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostOfSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_3b7cca2c-7a5e-4c22-b971-e9e112a5a04b" xlink:to="loc_us-gaap_CostOfSalesMember_e2b3984e-5596-4e8c-b11c-121f0c013170" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax_a315d998-06c6-4c4d-a3cc-ffb7f7bd4823" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_84e3962a-6c30-4b5c-a883-f2dbca705ab0" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax_a315d998-06c6-4c4d-a3cc-ffb7f7bd4823" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnDerivativeInstrumentsNetPretax_3b955555-15fe-4da2-b0fd-9d7ddeda6f96" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainLossOnDerivativeInstrumentsNetPretax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_84e3962a-6c30-4b5c-a883-f2dbca705ab0" xlink:to="loc_us-gaap_GainLossOnDerivativeInstrumentsNetPretax_3b955555-15fe-4da2-b0fd-9d7ddeda6f96" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateCashFlowHedgeGainLossToBeReclassifiedDuringNext12MonthsNet_3b7569e3-59e8-4ad3-aa5a-3b221262f1bd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestRateCashFlowHedgeGainLossToBeReclassifiedDuringNext12MonthsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_84e3962a-6c30-4b5c-a883-f2dbca705ab0" xlink:to="loc_us-gaap_InterestRateCashFlowHedgeGainLossToBeReclassifiedDuringNext12MonthsNet_3b7569e3-59e8-4ad3-aa5a-3b221262f1bd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_ebfb42ef-ad90-40c2-9300-c2ae807dbc4b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_84e3962a-6c30-4b5c-a883-f2dbca705ab0" xlink:to="loc_us-gaap_DerivativeNotionalAmount_ebfb42ef-ad90-40c2-9300-c2ae807dbc4b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_IntercompanyLoanQuarterlyPayment_4455a1e4-67f7-4cbe-b641-70b39fd4efe8" xlink:href="iart-20250930.xsd#iart_IntercompanyLoanQuarterlyPayment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_84e3962a-6c30-4b5c-a883-f2dbca705ab0" xlink:to="loc_iart_IntercompanyLoanQuarterlyPayment_4455a1e4-67f7-4cbe-b641-70b39fd4efe8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_fa546898-0a5a-439b-9b99-967802195600" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_84e3962a-6c30-4b5c-a883-f2dbca705ab0" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_fa546898-0a5a-439b-9b99-967802195600" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet_5703ab2c-c76b-440b-9fca-327e13c36e09" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_84e3962a-6c30-4b5c-a883-f2dbca705ab0" xlink:to="loc_us-gaap_DerivativeAssetsLiabilitiesAtFairValueNet_5703ab2c-c76b-440b-9fca-327e13c36e09" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/DERIVATIVEINSTRUMENTSScheduleofCrossCurrencySwapDerivativesDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#DERIVATIVEINSTRUMENTSScheduleofCrossCurrencySwapDerivativesDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/DERIVATIVEINSTRUMENTSScheduleofCrossCurrencySwapDerivativesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_61561e70-bd5b-4314-929b-2419bcf385c0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_a48b0226-b008-47bd-9ae3-2b286e562ae8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_61561e70-bd5b-4314-929b-2419bcf385c0" xlink:to="loc_us-gaap_DerivativeTable_a48b0226-b008-47bd-9ae3-2b286e562ae8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_805b98de-50f5-42ba-8fe7-dc132b657452" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_a48b0226-b008-47bd-9ae3-2b286e562ae8" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_805b98de-50f5-42ba-8fe7-dc132b657452" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_805b98de-50f5-42ba-8fe7-dc132b657452_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_805b98de-50f5-42ba-8fe7-dc132b657452" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_805b98de-50f5-42ba-8fe7-dc132b657452_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_b57ec216-e602-4ccb-bd00-a93bb07b28d1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_805b98de-50f5-42ba-8fe7-dc132b657452" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_b57ec216-e602-4ccb-bd00-a93bb07b28d1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CrossCurrencyInterestRateContractOneMember_12cea077-ec2f-45fa-b7d3-9e89a53a13c6" xlink:href="iart-20250930.xsd#iart_CrossCurrencyInterestRateContractOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_b57ec216-e602-4ccb-bd00-a93bb07b28d1" xlink:to="loc_iart_CrossCurrencyInterestRateContractOneMember_12cea077-ec2f-45fa-b7d3-9e89a53a13c6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CrossCurrencyInterestRateContractTwoMember_01c0cec3-d1e7-41e1-989f-023a46095630" xlink:href="iart-20250930.xsd#iart_CrossCurrencyInterestRateContractTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_b57ec216-e602-4ccb-bd00-a93bb07b28d1" xlink:to="loc_iart_CrossCurrencyInterestRateContractTwoMember_01c0cec3-d1e7-41e1-989f-023a46095630" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CrossCurrencyInterestRateContractMember_ae34e54b-f946-4974-b386-a739971d2839" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CrossCurrencyInterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_b57ec216-e602-4ccb-bd00-a93bb07b28d1" xlink:to="loc_us-gaap_CrossCurrencyInterestRateContractMember_ae34e54b-f946-4974-b386-a739971d2839" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_b705f388-a0cd-4a24-b55f-d0baa7e747b5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_a48b0226-b008-47bd-9ae3-2b286e562ae8" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_b705f388-a0cd-4a24-b55f-d0baa7e747b5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_b705f388-a0cd-4a24-b55f-d0baa7e747b5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_b705f388-a0cd-4a24-b55f-d0baa7e747b5" xlink:to="loc_us-gaap_HedgingRelationshipDomain_b705f388-a0cd-4a24-b55f-d0baa7e747b5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_f1a13f11-0719-4469-8883-1bf1e53e375c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_b705f388-a0cd-4a24-b55f-d0baa7e747b5" xlink:to="loc_us-gaap_HedgingRelationshipDomain_f1a13f11-0719-4469-8883-1bf1e53e375c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_e3a8a926-0251-4e2a-8c4d-ec4d4208142c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashFlowHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_f1a13f11-0719-4469-8883-1bf1e53e375c" xlink:to="loc_us-gaap_CashFlowHedgingMember_e3a8a926-0251-4e2a-8c4d-ec4d4208142c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_2cb024f1-3d3e-44e4-9370-ebaf548537a9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_a48b0226-b008-47bd-9ae3-2b286e562ae8" xlink:to="loc_us-gaap_HedgingDesignationAxis_2cb024f1-3d3e-44e4-9370-ebaf548537a9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_2cb024f1-3d3e-44e4-9370-ebaf548537a9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_2cb024f1-3d3e-44e4-9370-ebaf548537a9" xlink:to="loc_us-gaap_HedgingDesignationDomain_2cb024f1-3d3e-44e4-9370-ebaf548537a9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_c7f0af96-0dd1-4846-8da2-aa1e6e3d495a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_2cb024f1-3d3e-44e4-9370-ebaf548537a9" xlink:to="loc_us-gaap_HedgingDesignationDomain_c7f0af96-0dd1-4846-8da2-aa1e6e3d495a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_8236238f-921c-4a78-97e8-a6b046f2c63b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_c7f0af96-0dd1-4846-8da2-aa1e6e3d495a" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_8236238f-921c-4a78-97e8-a6b046f2c63b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PositionAxis_3d56f052-21e3-4fe8-a3b4-0820cd0d3ba8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PositionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_a48b0226-b008-47bd-9ae3-2b286e562ae8" xlink:to="loc_us-gaap_PositionAxis_3d56f052-21e3-4fe8-a3b4-0820cd0d3ba8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PositionDomain_3d56f052-21e3-4fe8-a3b4-0820cd0d3ba8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PositionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PositionAxis_3d56f052-21e3-4fe8-a3b4-0820cd0d3ba8" xlink:to="loc_us-gaap_PositionDomain_3d56f052-21e3-4fe8-a3b4-0820cd0d3ba8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PositionDomain_fe912ea3-d71c-40e5-97f8-6bca20676f5f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PositionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PositionAxis_3d56f052-21e3-4fe8-a3b4-0820cd0d3ba8" xlink:to="loc_us-gaap_PositionDomain_fe912ea3-d71c-40e5-97f8-6bca20676f5f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongMember_5acaf3c0-97e3-4934-b760-327b34484f88" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PositionDomain_fe912ea3-d71c-40e5-97f8-6bca20676f5f" xlink:to="loc_us-gaap_LongMember_5acaf3c0-97e3-4934-b760-327b34484f88" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortMember_2d93fc48-7da7-40b4-884c-700de3c0a452" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShortMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PositionDomain_fe912ea3-d71c-40e5-97f8-6bca20676f5f" xlink:to="loc_us-gaap_ShortMember_2d93fc48-7da7-40b4-884c-700de3c0a452" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFixedInterestRate_d21a9277-6356-4cd0-aa20-edf396432789" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeFixedInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_61561e70-bd5b-4314-929b-2419bcf385c0" xlink:to="loc_us-gaap_DerivativeFixedInterestRate_d21a9277-6356-4cd0-aa20-edf396432789" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_e0021d92-2ae9-4921-b918-5527c1c32523" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_61561e70-bd5b-4314-929b-2419bcf385c0" xlink:to="loc_us-gaap_DerivativeNotionalAmount_e0021d92-2ae9-4921-b918-5527c1c32523" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeNet_e77b3e72-c151-4dcb-82e5-d69e52e6237f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeFairValueOfDerivativeNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_61561e70-bd5b-4314-929b-2419bcf385c0" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeNet_e77b3e72-c151-4dcb-82e5-d69e52e6237f" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/DERIVATIVEINSTRUMENTSScheduleofNetInvestmentHedgesDerivativesDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#DERIVATIVEINSTRUMENTSScheduleofNetInvestmentHedgesDerivativesDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/DERIVATIVEINSTRUMENTSScheduleofNetInvestmentHedgesDerivativesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_6d418770-94cf-4027-9eca-771762fd4afc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_9092c273-7612-4be7-90d3-0c376620d2e5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_6d418770-94cf-4027-9eca-771762fd4afc" xlink:to="loc_us-gaap_DerivativeTable_9092c273-7612-4be7-90d3-0c376620d2e5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_ad4f4de0-0bc7-4c5b-84ae-7db734a3b803" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_9092c273-7612-4be7-90d3-0c376620d2e5" xlink:to="loc_us-gaap_HedgingDesignationAxis_ad4f4de0-0bc7-4c5b-84ae-7db734a3b803" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_ad4f4de0-0bc7-4c5b-84ae-7db734a3b803_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_ad4f4de0-0bc7-4c5b-84ae-7db734a3b803" xlink:to="loc_us-gaap_HedgingDesignationDomain_ad4f4de0-0bc7-4c5b-84ae-7db734a3b803_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_a280b5ab-61e5-4e30-8bff-4027b3d584fa" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_ad4f4de0-0bc7-4c5b-84ae-7db734a3b803" xlink:to="loc_us-gaap_HedgingDesignationDomain_a280b5ab-61e5-4e30-8bff-4027b3d584fa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_db392def-9399-443a-830a-9c4438a1717e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_a280b5ab-61e5-4e30-8bff-4027b3d584fa" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_db392def-9399-443a-830a-9c4438a1717e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_2fe57fbb-ba94-42b3-98bb-4cb2d3c96fa1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_9092c273-7612-4be7-90d3-0c376620d2e5" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_2fe57fbb-ba94-42b3-98bb-4cb2d3c96fa1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_2fe57fbb-ba94-42b3-98bb-4cb2d3c96fa1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_2fe57fbb-ba94-42b3-98bb-4cb2d3c96fa1" xlink:to="loc_us-gaap_HedgingRelationshipDomain_2fe57fbb-ba94-42b3-98bb-4cb2d3c96fa1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_a163da9f-9f1a-4958-aeb9-d6af1e59e160" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_2fe57fbb-ba94-42b3-98bb-4cb2d3c96fa1" xlink:to="loc_us-gaap_HedgingRelationshipDomain_a163da9f-9f1a-4958-aeb9-d6af1e59e160" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetInvestmentHedgingMember_1d00a10e-1bb8-4c91-81a5-bc0711600fca" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetInvestmentHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_a163da9f-9f1a-4958-aeb9-d6af1e59e160" xlink:to="loc_us-gaap_NetInvestmentHedgingMember_1d00a10e-1bb8-4c91-81a5-bc0711600fca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_39d5f460-072c-4de0-a26c-a82d76b80657" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_9092c273-7612-4be7-90d3-0c376620d2e5" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_39d5f460-072c-4de0-a26c-a82d76b80657" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_39d5f460-072c-4de0-a26c-a82d76b80657_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_39d5f460-072c-4de0-a26c-a82d76b80657" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_39d5f460-072c-4de0-a26c-a82d76b80657_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_c7a1326c-2a77-45c5-b920-8069beb0471e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_39d5f460-072c-4de0-a26c-a82d76b80657" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_c7a1326c-2a77-45c5-b920-8069beb0471e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CrossCurrencyInterestRateContractMember_b6e2c8d1-d36b-4f56-a28d-bdd31c7df482" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CrossCurrencyInterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c7a1326c-2a77-45c5-b920-8069beb0471e" xlink:to="loc_us-gaap_CrossCurrencyInterestRateContractMember_b6e2c8d1-d36b-4f56-a28d-bdd31c7df482" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CrossCurrencyInterestRateContractOneMember_6ec5adc2-d621-455f-99f6-514629ca6b5d" xlink:href="iart-20250930.xsd#iart_CrossCurrencyInterestRateContractOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CrossCurrencyInterestRateContractMember_b6e2c8d1-d36b-4f56-a28d-bdd31c7df482" xlink:to="loc_iart_CrossCurrencyInterestRateContractOneMember_6ec5adc2-d621-455f-99f6-514629ca6b5d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CrossCurrencyInterestRateContractTwoMember_0d07c494-36de-4836-9b06-51f67359a86f" xlink:href="iart-20250930.xsd#iart_CrossCurrencyInterestRateContractTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CrossCurrencyInterestRateContractMember_b6e2c8d1-d36b-4f56-a28d-bdd31c7df482" xlink:to="loc_iart_CrossCurrencyInterestRateContractTwoMember_0d07c494-36de-4836-9b06-51f67359a86f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CrossCurrencyInterestRateContractThreeMember_2d1d1727-aae5-4432-b817-b21b287497d6" xlink:href="iart-20250930.xsd#iart_CrossCurrencyInterestRateContractThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CrossCurrencyInterestRateContractMember_b6e2c8d1-d36b-4f56-a28d-bdd31c7df482" xlink:to="loc_iart_CrossCurrencyInterestRateContractThreeMember_2d1d1727-aae5-4432-b817-b21b287497d6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CrossCurrencyInterestRateContractFourMember_522642b8-eb88-4004-8e22-d82bdf45ad3c" xlink:href="iart-20250930.xsd#iart_CrossCurrencyInterestRateContractFourMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CrossCurrencyInterestRateContractMember_b6e2c8d1-d36b-4f56-a28d-bdd31c7df482" xlink:to="loc_iart_CrossCurrencyInterestRateContractFourMember_522642b8-eb88-4004-8e22-d82bdf45ad3c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CrossCurrencyInterestRateContractFiveMember_7cc8e0fd-3293-4475-9054-cd6df61bfb43" xlink:href="iart-20250930.xsd#iart_CrossCurrencyInterestRateContractFiveMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CrossCurrencyInterestRateContractMember_b6e2c8d1-d36b-4f56-a28d-bdd31c7df482" xlink:to="loc_iart_CrossCurrencyInterestRateContractFiveMember_7cc8e0fd-3293-4475-9054-cd6df61bfb43" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CrossCurrencyInterestRateContractSixMember_c68bd3a7-e9d2-4d3e-ad28-a46934d20087" xlink:href="iart-20250930.xsd#iart_CrossCurrencyInterestRateContractSixMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CrossCurrencyInterestRateContractMember_b6e2c8d1-d36b-4f56-a28d-bdd31c7df482" xlink:to="loc_iart_CrossCurrencyInterestRateContractSixMember_c68bd3a7-e9d2-4d3e-ad28-a46934d20087" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PositionAxis_7d4a9cad-2b8d-49c2-9f82-5e37e6bae3ee" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PositionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_9092c273-7612-4be7-90d3-0c376620d2e5" xlink:to="loc_us-gaap_PositionAxis_7d4a9cad-2b8d-49c2-9f82-5e37e6bae3ee" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PositionDomain_7d4a9cad-2b8d-49c2-9f82-5e37e6bae3ee_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PositionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PositionAxis_7d4a9cad-2b8d-49c2-9f82-5e37e6bae3ee" xlink:to="loc_us-gaap_PositionDomain_7d4a9cad-2b8d-49c2-9f82-5e37e6bae3ee_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PositionDomain_b8c23697-333e-436a-bc60-52df4438fe6c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PositionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PositionAxis_7d4a9cad-2b8d-49c2-9f82-5e37e6bae3ee" xlink:to="loc_us-gaap_PositionDomain_b8c23697-333e-436a-bc60-52df4438fe6c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongMember_96060a0f-f3dd-40fe-97a0-49ede1ad4efd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PositionDomain_b8c23697-333e-436a-bc60-52df4438fe6c" xlink:to="loc_us-gaap_LongMember_96060a0f-f3dd-40fe-97a0-49ede1ad4efd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortMember_eab89b8e-a8be-4f76-937b-e5013da14dab" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShortMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PositionDomain_b8c23697-333e-436a-bc60-52df4438fe6c" xlink:to="loc_us-gaap_ShortMember_eab89b8e-a8be-4f76-937b-e5013da14dab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFixedInterestRate_acb614a4-9c71-405c-9b64-f128ae9b507c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeFixedInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_6d418770-94cf-4027-9eca-771762fd4afc" xlink:to="loc_us-gaap_DerivativeFixedInterestRate_acb614a4-9c71-405c-9b64-f128ae9b507c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_357f6a95-7e8c-4296-9f7e-4704043f2d63" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_6d418770-94cf-4027-9eca-771762fd4afc" xlink:to="loc_us-gaap_DerivativeNotionalAmount_357f6a95-7e8c-4296-9f7e-4704043f2d63" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeNet_6edd9f2a-1992-452e-87a0-bc5556610179" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeFairValueOfDerivativeNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_6d418770-94cf-4027-9eca-771762fd4afc" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeNet_6edd9f2a-1992-452e-87a0-bc5556610179" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/DERIVATIVEINSTRUMENTSFairValueofDerivativeInstrumentsByBalanceSheetLocationDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#DERIVATIVEINSTRUMENTSFairValueofDerivativeInstrumentsByBalanceSheetLocationDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/DERIVATIVEINSTRUMENTSFairValueofDerivativeInstrumentsByBalanceSheetLocationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativesFairValueLineItems_0d56f527-4370-48ce-9608-363ef81418f9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativesFairValueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_135ae382-b8cc-482f-a3b3-4e11a680ebab" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_0d56f527-4370-48ce-9608-363ef81418f9" xlink:to="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_135ae382-b8cc-482f-a3b3-4e11a680ebab" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_00dcd71d-b06d-4b76-9d4a-20ab5d9ab757" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_135ae382-b8cc-482f-a3b3-4e11a680ebab" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_00dcd71d-b06d-4b76-9d4a-20ab5d9ab757" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_00dcd71d-b06d-4b76-9d4a-20ab5d9ab757_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_00dcd71d-b06d-4b76-9d4a-20ab5d9ab757" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_00dcd71d-b06d-4b76-9d4a-20ab5d9ab757_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_c8f88608-c362-46fb-bfeb-9ae464fc038a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_00dcd71d-b06d-4b76-9d4a-20ab5d9ab757" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_c8f88608-c362-46fb-bfeb-9ae464fc038a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_1126cc9b-f1e2-4b84-ae83-988eb78c29ec" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c8f88608-c362-46fb-bfeb-9ae464fc038a" xlink:to="loc_us-gaap_InterestRateSwapMember_1126cc9b-f1e2-4b84-ae83-988eb78c29ec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CrossCurrencyInterestRateContractMember_176d0c99-28c8-45bc-918c-d6d25cfa63f1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CrossCurrencyInterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c8f88608-c362-46fb-bfeb-9ae464fc038a" xlink:to="loc_us-gaap_CrossCurrencyInterestRateContractMember_176d0c99-28c8-45bc-918c-d6d25cfa63f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeForwardMember_b40a6e89-351b-4721-b766-cb7c61523a2b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignExchangeForwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c8f88608-c362-46fb-bfeb-9ae464fc038a" xlink:to="loc_us-gaap_ForeignExchangeForwardMember_b40a6e89-351b-4721-b766-cb7c61523a2b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_d6ba44cb-ea83-42c9-a62b-9f4cf76d7415" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_135ae382-b8cc-482f-a3b3-4e11a680ebab" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_d6ba44cb-ea83-42c9-a62b-9f4cf76d7415" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_d6ba44cb-ea83-42c9-a62b-9f4cf76d7415_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_d6ba44cb-ea83-42c9-a62b-9f4cf76d7415" xlink:to="loc_us-gaap_HedgingRelationshipDomain_d6ba44cb-ea83-42c9-a62b-9f4cf76d7415_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_7f73d3af-18d3-4d60-8b23-0873e9804205" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_d6ba44cb-ea83-42c9-a62b-9f4cf76d7415" xlink:to="loc_us-gaap_HedgingRelationshipDomain_7f73d3af-18d3-4d60-8b23-0873e9804205" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_28ceadd9-de1b-40e8-b135-228390bca629" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashFlowHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_7f73d3af-18d3-4d60-8b23-0873e9804205" xlink:to="loc_us-gaap_CashFlowHedgingMember_28ceadd9-de1b-40e8-b135-228390bca629" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetInvestmentHedgingMember_4bc9af31-b6c4-45a7-99b9-76c444f159e1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetInvestmentHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_7f73d3af-18d3-4d60-8b23-0873e9804205" xlink:to="loc_us-gaap_NetInvestmentHedgingMember_4bc9af31-b6c4-45a7-99b9-76c444f159e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_5170a51d-cc27-4282-866f-a02032c3e541" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_135ae382-b8cc-482f-a3b3-4e11a680ebab" xlink:to="loc_us-gaap_HedgingDesignationAxis_5170a51d-cc27-4282-866f-a02032c3e541" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_5170a51d-cc27-4282-866f-a02032c3e541_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_5170a51d-cc27-4282-866f-a02032c3e541" xlink:to="loc_us-gaap_HedgingDesignationDomain_5170a51d-cc27-4282-866f-a02032c3e541_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_0a708afd-599e-401a-867d-ec02836c37d3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_5170a51d-cc27-4282-866f-a02032c3e541" xlink:to="loc_us-gaap_HedgingDesignationDomain_0a708afd-599e-401a-867d-ec02836c37d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_524440ce-c88b-4a83-b999-e82276dd7dd5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_0a708afd-599e-401a-867d-ec02836c37d3" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_524440ce-c88b-4a83-b999-e82276dd7dd5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_d7f9cd95-72e7-474f-8886-b446669984ec" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_135ae382-b8cc-482f-a3b3-4e11a680ebab" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_d7f9cd95-72e7-474f-8886-b446669984ec" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_d7f9cd95-72e7-474f-8886-b446669984ec_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_d7f9cd95-72e7-474f-8886-b446669984ec" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_d7f9cd95-72e7-474f-8886-b446669984ec_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_96b0b131-758b-41b1-9a28-f48fa6d67e71" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_d7f9cd95-72e7-474f-8886-b446669984ec" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_96b0b131-758b-41b1-9a28-f48fa6d67e71" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember_1a9e947c-8e4c-4083-a95b-176203aaf2af" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_96b0b131-758b-41b1-9a28-f48fa6d67e71" xlink:to="loc_us-gaap_PrepaidExpensesAndOtherCurrentAssetsMember_1a9e947c-8e4c-4083-a95b-176203aaf2af" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsMember_b2c4088f-834e-4a2b-9fb6-976dfd88bd3d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_96b0b131-758b-41b1-9a28-f48fa6d67e71" xlink:to="loc_us-gaap_OtherAssetsMember_b2c4088f-834e-4a2b-9fb6-976dfd88bd3d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_AccruedExpensesAndOtherCurrentLiabilitiesMember_b22e0124-8389-4a93-9ac9-5348d5828ffb" xlink:href="iart-20250930.xsd#iart_AccruedExpensesAndOtherCurrentLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_96b0b131-758b-41b1-9a28-f48fa6d67e71" xlink:to="loc_iart_AccruedExpensesAndOtherCurrentLiabilitiesMember_b22e0124-8389-4a93-9ac9-5348d5828ffb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesMember_c569ff68-d01b-4d22-8046-6817462fc5f0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_96b0b131-758b-41b1-9a28-f48fa6d67e71" xlink:to="loc_us-gaap_OtherLiabilitiesMember_c569ff68-d01b-4d22-8046-6817462fc5f0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_821c8b46-e0d8-45a8-ae88-cecbf29a84b6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeFairValueOfDerivativeAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_0d56f527-4370-48ce-9608-363ef81418f9" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeAsset_821c8b46-e0d8-45a8-ae88-cecbf29a84b6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_50d5495b-b53d-4ec4-a123-8aec030dfd89" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeFairValueOfDerivativeLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativesFairValueLineItems_0d56f527-4370-48ce-9608-363ef81418f9" xlink:to="loc_us-gaap_DerivativeFairValueOfDerivativeLiability_50d5495b-b53d-4ec4-a123-8aec030dfd89" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/DERIVATIVEINSTRUMENTSEffectofDerivativeInstrumentsDesignatedCashFlowHedgesonStatementsofOperationsDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#DERIVATIVEINSTRUMENTSEffectofDerivativeInstrumentsDesignatedCashFlowHedgesonStatementsofOperationsDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/DERIVATIVEINSTRUMENTSEffectofDerivativeInstrumentsDesignatedCashFlowHedgesonStatementsofOperationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_66e8e9f4-6ebd-456a-8caa-124ec979f934" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_d51b861e-1c13-42b2-993a-ec18c1ecf604" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_66e8e9f4-6ebd-456a-8caa-124ec979f934" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_d51b861e-1c13-42b2-993a-ec18c1ecf604" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_3c38274f-acc9-4a9d-b754-d93ce61c2c9f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_d51b861e-1c13-42b2-993a-ec18c1ecf604" xlink:to="loc_us-gaap_HedgingDesignationAxis_3c38274f-acc9-4a9d-b754-d93ce61c2c9f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_3c38274f-acc9-4a9d-b754-d93ce61c2c9f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_3c38274f-acc9-4a9d-b754-d93ce61c2c9f" xlink:to="loc_us-gaap_HedgingDesignationDomain_3c38274f-acc9-4a9d-b754-d93ce61c2c9f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_00b7334b-1534-4963-a5c9-f3dd3c8f92d2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_3c38274f-acc9-4a9d-b754-d93ce61c2c9f" xlink:to="loc_us-gaap_HedgingDesignationDomain_00b7334b-1534-4963-a5c9-f3dd3c8f92d2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_907e99e1-a2d8-4836-a65e-2301153cdba5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_00b7334b-1534-4963-a5c9-f3dd3c8f92d2" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_907e99e1-a2d8-4836-a65e-2301153cdba5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_5a434307-1624-456d-a36d-fb43aef783b4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_d51b861e-1c13-42b2-993a-ec18c1ecf604" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_5a434307-1624-456d-a36d-fb43aef783b4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_5a434307-1624-456d-a36d-fb43aef783b4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_5a434307-1624-456d-a36d-fb43aef783b4" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_5a434307-1624-456d-a36d-fb43aef783b4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_bae9fcf4-b9ea-4a40-b0f6-725eac9606a1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_5a434307-1624-456d-a36d-fb43aef783b4" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_bae9fcf4-b9ea-4a40-b0f6-725eac9606a1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_2a9ccd9b-702d-4f66-8a7f-bc78d1461295" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_bae9fcf4-b9ea-4a40-b0f6-725eac9606a1" xlink:to="loc_us-gaap_InterestRateSwapMember_2a9ccd9b-702d-4f66-8a7f-bc78d1461295" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CrossCurrencyInterestRateContractMember_0b9d1ca3-ca5b-4a1b-ae9d-722996d38178" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CrossCurrencyInterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_bae9fcf4-b9ea-4a40-b0f6-725eac9606a1" xlink:to="loc_us-gaap_CrossCurrencyInterestRateContractMember_0b9d1ca3-ca5b-4a1b-ae9d-722996d38178" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeForwardMember_fd603105-3ac7-42f2-adba-1c59ab1cbc83" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignExchangeForwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_bae9fcf4-b9ea-4a40-b0f6-725eac9606a1" xlink:to="loc_us-gaap_ForeignExchangeForwardMember_fd603105-3ac7-42f2-adba-1c59ab1cbc83" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_a2957436-a7f7-431f-944f-664fde30c77f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_d51b861e-1c13-42b2-993a-ec18c1ecf604" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_a2957436-a7f7-431f-944f-664fde30c77f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_a2957436-a7f7-431f-944f-664fde30c77f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_a2957436-a7f7-431f-944f-664fde30c77f" xlink:to="loc_us-gaap_HedgingRelationshipDomain_a2957436-a7f7-431f-944f-664fde30c77f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_d4ab55b1-5f36-4676-8a4d-cb68cf956f6b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_a2957436-a7f7-431f-944f-664fde30c77f" xlink:to="loc_us-gaap_HedgingRelationshipDomain_d4ab55b1-5f36-4676-8a4d-cb68cf956f6b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_6218f71b-8be2-41c7-9d36-fa98dc7757a5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashFlowHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_d4ab55b1-5f36-4676-8a4d-cb68cf956f6b" xlink:to="loc_us-gaap_CashFlowHedgingMember_6218f71b-8be2-41c7-9d36-fa98dc7757a5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetInvestmentHedgingMember_5916ca86-facf-4685-99ab-d226ef73e669" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetInvestmentHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_d4ab55b1-5f36-4676-8a4d-cb68cf956f6b" xlink:to="loc_us-gaap_NetInvestmentHedgingMember_5916ca86-facf-4685-99ab-d226ef73e669" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_9e3c8731-a357-4532-a1b4-40fedcde724b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_d51b861e-1c13-42b2-993a-ec18c1ecf604" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_9e3c8731-a357-4532-a1b4-40fedcde724b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_9e3c8731-a357-4532-a1b4-40fedcde724b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_9e3c8731-a357-4532-a1b4-40fedcde724b" xlink:to="loc_us-gaap_EquityComponentDomain_9e3c8731-a357-4532-a1b4-40fedcde724b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_13bf60fd-b132-486f-8164-46499cc26a03" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_9e3c8731-a357-4532-a1b4-40fedcde724b" xlink:to="loc_us-gaap_EquityComponentDomain_13bf60fd-b132-486f-8164-46499cc26a03" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_f14bd3fe-620d-4b66-b492-41a744212329" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_13bf60fd-b132-486f-8164-46499cc26a03" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_f14bd3fe-620d-4b66-b492-41a744212329" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_af819d6e-9f7a-4436-88b1-ebcbed74d853" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AOCIAttributableToParentNetOfTaxRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_66e8e9f4-6ebd-456a-8caa-124ec979f934" xlink:to="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_af819d6e-9f7a-4436-88b1-ebcbed74d853" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_1c11e85b-5dd7-44e3-8ccc-1c26bc7079a4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_af819d6e-9f7a-4436-88b1-ebcbed74d853" xlink:to="loc_us-gaap_StockholdersEquity_1c11e85b-5dd7-44e3-8ccc-1c26bc7079a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_2ec59a08-3865-4b99-a66e-73a4452b0856" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_af819d6e-9f7a-4436-88b1-ebcbed74d853" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_2ec59a08-3865-4b99-a66e-73a4452b0856" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax_163865f9-96d6-4f7a-9fb0-146dfd68f5a6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_af819d6e-9f7a-4436-88b1-ebcbed74d853" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationAfterTax_163865f9-96d6-4f7a-9fb0-146dfd68f5a6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_910b19a5-a855-418f-a808-ab33b0b7c790" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/DERIVATIVEINSTRUMENTSScheduleofDerivativesNotDesignatedasHedgingInstrumentsDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#DERIVATIVEINSTRUMENTSScheduleofDerivativesNotDesignatedasHedgingInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/DERIVATIVEINSTRUMENTSScheduleofDerivativesNotDesignatedasHedgingInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_b7640a01-2441-46b1-b19f-aa11ebbd6798" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_f18751d2-503d-4d2b-934a-cf6b4852306f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_b7640a01-2441-46b1-b19f-aa11ebbd6798" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_f18751d2-503d-4d2b-934a-cf6b4852306f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_96da26ae-e57e-4639-b510-4ef585af7404" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_f18751d2-503d-4d2b-934a-cf6b4852306f" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_96da26ae-e57e-4639-b510-4ef585af7404" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_96da26ae-e57e-4639-b510-4ef585af7404_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_96da26ae-e57e-4639-b510-4ef585af7404" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_96da26ae-e57e-4639-b510-4ef585af7404_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_12342fc7-745a-4b61-9fed-25d22f1591a7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_96da26ae-e57e-4639-b510-4ef585af7404" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_12342fc7-745a-4b61-9fed-25d22f1591a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeForwardMember_f9b4aa8e-2ce2-4e9d-886b-f9c8c1693de1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignExchangeForwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_12342fc7-745a-4b61-9fed-25d22f1591a7" xlink:to="loc_us-gaap_ForeignExchangeForwardMember_f9b4aa8e-2ce2-4e9d-886b-f9c8c1693de1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrencySwapMember_319dc360-b92f-4a2f-97cc-56a483bc9c23" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CurrencySwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_12342fc7-745a-4b61-9fed-25d22f1591a7" xlink:to="loc_us-gaap_CurrencySwapMember_319dc360-b92f-4a2f-97cc-56a483bc9c23" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet_247ecdb8-7703-4fd2-b3f8-2072ef8739a6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_b7640a01-2441-46b1-b19f-aa11ebbd6798" xlink:to="loc_us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet_247ecdb8-7703-4fd2-b3f8-2072ef8739a6" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/STOCKBASEDCOMPENSATIONDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#STOCKBASEDCOMPENSATIONDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/STOCKBASEDCOMPENSATIONDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0f462f7c-3bc7-4003-b60d-a39babc5a252" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_cb31bf68-3273-49de-abfd-d36090459fec" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0f462f7c-3bc7-4003-b60d-a39babc5a252" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_cb31bf68-3273-49de-abfd-d36090459fec" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_1330b4ca-1535-4b4b-926d-c0f11a05ea4e" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_cb31bf68-3273-49de-abfd-d36090459fec" xlink:to="loc_srt_RangeAxis_1330b4ca-1535-4b4b-926d-c0f11a05ea4e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_1330b4ca-1535-4b4b-926d-c0f11a05ea4e_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_1330b4ca-1535-4b4b-926d-c0f11a05ea4e" xlink:to="loc_srt_RangeMember_1330b4ca-1535-4b4b-926d-c0f11a05ea4e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_86e67c98-fb2e-4bf4-b9f0-acf8f9979fef" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_1330b4ca-1535-4b4b-926d-c0f11a05ea4e" xlink:to="loc_srt_RangeMember_86e67c98-fb2e-4bf4-b9f0-acf8f9979fef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_95fc0c0d-180d-46e8-861c-bdf1b056216e" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_86e67c98-fb2e-4bf4-b9f0-acf8f9979fef" xlink:to="loc_srt_MaximumMember_95fc0c0d-180d-46e8-861c-bdf1b056216e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_3861de42-36fb-42e1-ae7d-edf07ee90efe" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_86e67c98-fb2e-4bf4-b9f0-acf8f9979fef" xlink:to="loc_srt_MinimumMember_3861de42-36fb-42e1-ae7d-edf07ee90efe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_4836ff8f-6fd3-47c2-a783-4030c1deb6c1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_cb31bf68-3273-49de-abfd-d36090459fec" xlink:to="loc_us-gaap_AwardTypeAxis_4836ff8f-6fd3-47c2-a783-4030c1deb6c1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4836ff8f-6fd3-47c2-a783-4030c1deb6c1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_4836ff8f-6fd3-47c2-a783-4030c1deb6c1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_4836ff8f-6fd3-47c2-a783-4030c1deb6c1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0e833c98-37d1-4c33-be1b-e550e7d0fef0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_4836ff8f-6fd3-47c2-a783-4030c1deb6c1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0e833c98-37d1-4c33-be1b-e550e7d0fef0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_90f4402d-54ee-4f5a-8a23-4fffd2cc6e2e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0e833c98-37d1-4c33-be1b-e550e7d0fef0" xlink:to="loc_us-gaap_EmployeeStockOptionMember_90f4402d-54ee-4f5a-8a23-4fffd2cc6e2e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_36a0168b-e75d-4aa8-ae0a-5f1b2cf2ad33" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0e833c98-37d1-4c33-be1b-e550e7d0fef0" xlink:to="loc_us-gaap_RestrictedStockMember_36a0168b-e75d-4aa8-ae0a-5f1b2cf2ad33" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_192581bb-c47b-4be1-a47a-0d67d42dbcf3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0e833c98-37d1-4c33-be1b-e550e7d0fef0" xlink:to="loc_us-gaap_PerformanceSharesMember_192581bb-c47b-4be1-a47a-0d67d42dbcf3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_28aa3f6e-487d-44ce-91b7-508cefec457d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_0e833c98-37d1-4c33-be1b-e550e7d0fef0" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_28aa3f6e-487d-44ce-91b7-508cefec457d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_b45f98e2-88c1-45d6-b3d3-ec3646a55593" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_TitleOfIndividualAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_cb31bf68-3273-49de-abfd-d36090459fec" xlink:to="loc_srt_TitleOfIndividualAxis_b45f98e2-88c1-45d6-b3d3-ec3646a55593" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_b45f98e2-88c1-45d6-b3d3-ec3646a55593_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_TitleOfIndividualAxis_b45f98e2-88c1-45d6-b3d3-ec3646a55593" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_b45f98e2-88c1-45d6-b3d3-ec3646a55593_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_f2d8737a-08e6-4d20-b6e6-8789b39e7f3f" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_TitleOfIndividualAxis_b45f98e2-88c1-45d6-b3d3-ec3646a55593" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_f2d8737a-08e6-4d20-b6e6-8789b39e7f3f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_DirectorMember_8fd21b81-8aaf-4337-b264-f2e771b8dd0d" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_DirectorMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_f2d8737a-08e6-4d20-b6e6-8789b39e7f3f" xlink:to="loc_srt_DirectorMember_8fd21b81-8aaf-4337-b264-f2e771b8dd0d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_EmployeeMember_16f2646b-538e-42c3-8205-734f88fa516f" xlink:href="iart-20250930.xsd#iart_EmployeeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_f2d8737a-08e6-4d20-b6e6-8789b39e7f3f" xlink:to="loc_iart_EmployeeMember_16f2646b-538e-42c3-8205-734f88fa516f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DirectorsandCertainExecutiveOfficersMember_cda14f08-8cf8-451f-b39d-74b89d13ba60" xlink:href="iart-20250930.xsd#iart_DirectorsandCertainExecutiveOfficersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_f2d8737a-08e6-4d20-b6e6-8789b39e7f3f" xlink:to="loc_iart_DirectorsandCertainExecutiveOfficersMember_cda14f08-8cf8-451f-b39d-74b89d13ba60" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_dfcd5f63-cb33-45b6-bd57-3806316e4326" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0f462f7c-3bc7-4003-b60d-a39babc5a252" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_dfcd5f63-cb33-45b6-bd57-3806316e4326" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_77043864-723d-419f-a96e-ff447a333423" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0f462f7c-3bc7-4003-b60d-a39babc5a252" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_77043864-723d-419f-a96e-ff447a333423" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_0b2af6e0-913c-4128-83b9-efef297eeec2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0f462f7c-3bc7-4003-b60d-a39babc5a252" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_0b2af6e0-913c-4128-83b9-efef297eeec2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_f2959684-ab2f-40b9-a036-6af4e1f8b6d7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0f462f7c-3bc7-4003-b60d-a39babc5a252" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_f2959684-ab2f-40b9-a036-6af4e1f8b6d7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod_16d504dd-cdde-4d33-ae41-f301ad8d707c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0f462f7c-3bc7-4003-b60d-a39babc5a252" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod_16d504dd-cdde-4d33-ae41-f301ad8d707c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_27b2c30d-a449-422d-9189-4d6219b3786e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0f462f7c-3bc7-4003-b60d-a39babc5a252" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_27b2c30d-a449-422d-9189-4d6219b3786e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_4d32d6ac-7eca-4925-be9a-c251c20c58e2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0f462f7c-3bc7-4003-b60d-a39babc5a252" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_4d32d6ac-7eca-4925-be9a-c251c20c58e2" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_25cf3fd1-09f3-4896-b897-0a8e40d8a7f7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0f462f7c-3bc7-4003-b60d-a39babc5a252" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_25cf3fd1-09f3-4896-b897-0a8e40d8a7f7" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/LEASESANDRELATEDPARTYLEASESNarrativeDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#LEASESANDRELATEDPARTYLEASESNarrativeDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/LEASESANDRELATEDPARTYLEASESNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeasedAssetsLineItems_b2daefe7-aba0-4e9b-b9af-01b90427cb38" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeasedAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfOperatingLeasedAssetsTable_c79548a1-efc3-483c-aa51-d16dda1039ee" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfOperatingLeasedAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_b2daefe7-aba0-4e9b-b9af-01b90427cb38" xlink:to="loc_us-gaap_ScheduleOfOperatingLeasedAssetsTable_c79548a1-efc3-483c-aa51-d16dda1039ee" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_c01152be-4d34-4994-a3a3-7e2418cbb427" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfOperatingLeasedAssetsTable_c79548a1-efc3-483c-aa51-d16dda1039ee" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_c01152be-4d34-4994-a3a3-7e2418cbb427" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_c01152be-4d34-4994-a3a3-7e2418cbb427_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_c01152be-4d34-4994-a3a3-7e2418cbb427" xlink:to="loc_us-gaap_RelatedPartyDomain_c01152be-4d34-4994-a3a3-7e2418cbb427_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_b2ad3b9c-fe0d-44b1-92c4-42c274bd4384" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_c01152be-4d34-4994-a3a3-7e2418cbb427" xlink:to="loc_us-gaap_RelatedPartyDomain_b2ad3b9c-fe0d-44b1-92c4-42c274bd4384" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyMember_9ae49ae7-daeb-4974-8c9a-5a5fbca0b3d8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RelatedPartyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_b2ad3b9c-fe0d-44b1-92c4-42c274bd4384" xlink:to="loc_us-gaap_RelatedPartyMember_9ae49ae7-daeb-4974-8c9a-5a5fbca0b3d8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AffiliatedEntityMember_e0d6cd24-0fe9-4af9-b0cb-d76726bd816a" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_AffiliatedEntityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_b2ad3b9c-fe0d-44b1-92c4-42c274bd4384" xlink:to="loc_srt_AffiliatedEntityMember_e0d6cd24-0fe9-4af9-b0cb-d76726bd816a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseContractualTermAxis_9e3c36b5-3148-4ecd-8eef-b7fd12fa00ea" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LeaseContractualTermAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfOperatingLeasedAssetsTable_c79548a1-efc3-483c-aa51-d16dda1039ee" xlink:to="loc_us-gaap_LeaseContractualTermAxis_9e3c36b5-3148-4ecd-8eef-b7fd12fa00ea" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseContractualTermDomain_9e3c36b5-3148-4ecd-8eef-b7fd12fa00ea_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LeaseContractualTermDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LeaseContractualTermAxis_9e3c36b5-3148-4ecd-8eef-b7fd12fa00ea" xlink:to="loc_us-gaap_LeaseContractualTermDomain_9e3c36b5-3148-4ecd-8eef-b7fd12fa00ea_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseContractualTermDomain_931c42c2-1e84-4ca9-9a1a-7756a0b9875d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LeaseContractualTermDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LeaseContractualTermAxis_9e3c36b5-3148-4ecd-8eef-b7fd12fa00ea" xlink:to="loc_us-gaap_LeaseContractualTermDomain_931c42c2-1e84-4ca9-9a1a-7756a0b9875d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_FiveYearOptionLeasePeriodOneMember_fcb7830e-e475-4e27-ab6c-8b87f1b119db" xlink:href="iart-20250930.xsd#iart_FiveYearOptionLeasePeriodOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LeaseContractualTermDomain_931c42c2-1e84-4ca9-9a1a-7756a0b9875d" xlink:to="loc_iart_FiveYearOptionLeasePeriodOneMember_fcb7830e-e475-4e27-ab6c-8b87f1b119db" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_FiveYearOptionLeasePeriodTwoMember_809e5e46-a155-4012-a439-f655b1b57982" xlink:href="iart-20250930.xsd#iart_FiveYearOptionLeasePeriodTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LeaseContractualTermDomain_931c42c2-1e84-4ca9-9a1a-7756a0b9875d" xlink:to="loc_iart_FiveYearOptionLeasePeriodTwoMember_809e5e46-a155-4012-a439-f655b1b57982" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_LesseeOperatingLeaseNumberOfRenewalOptions_f520b842-c2c7-4c6d-b15f-43a9b98ed27c" xlink:href="iart-20250930.xsd#iart_LesseeOperatingLeaseNumberOfRenewalOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_b2daefe7-aba0-4e9b-b9af-01b90427cb38" xlink:to="loc_iart_LesseeOperatingLeaseNumberOfRenewalOptions_f520b842-c2c7-4c6d-b15f-43a9b98ed27c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseExpense_cbaf764b-19ed-4e61-b08f-aa2d0a1e3a02" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_b2daefe7-aba0-4e9b-b9af-01b90427cb38" xlink:to="loc_us-gaap_OperatingLeaseExpense_cbaf764b-19ed-4e61-b08f-aa2d0a1e3a02" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDue_79e45e00-70b6-4873-9cb3-7020587e8ea7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_b2daefe7-aba0-4e9b-b9af-01b90427cb38" xlink:to="loc_us-gaap_FinanceLeaseLiabilityPaymentsDue_79e45e00-70b6-4873-9cb3-7020587e8ea7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_PercentOfManufacturingFacilityOwnedByCorporationWhoseShareholdersAreTrustsWhoseBeneficiariesIncludeFamilyMembersOfCompanysFormerDirector_b5c106f8-7484-46ee-8d54-695482248b69" xlink:href="iart-20250930.xsd#iart_PercentOfManufacturingFacilityOwnedByCorporationWhoseShareholdersAreTrustsWhoseBeneficiariesIncludeFamilyMembersOfCompanysFormerDirector"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_b2daefe7-aba0-4e9b-b9af-01b90427cb38" xlink:to="loc_iart_PercentOfManufacturingFacilityOwnedByCorporationWhoseShareholdersAreTrustsWhoseBeneficiariesIncludeFamilyMembersOfCompanysFormerDirector_b5c106f8-7484-46ee-8d54-695482248b69" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_AnnualRateOfLeaseAgreement_8c71c101-2d15-49e9-b324-b159454c7663" xlink:href="iart-20250930.xsd#iart_AnnualRateOfLeaseAgreement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_b2daefe7-aba0-4e9b-b9af-01b90427cb38" xlink:to="loc_iart_AnnualRateOfLeaseAgreement_8c71c101-2d15-49e9-b324-b159454c7663" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_OptionToExtendLeaseYears_afdc879e-13ab-450f-9455-2087939b7a15" xlink:href="iart-20250930.xsd#iart_OptionToExtendLeaseYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_b2daefe7-aba0-4e9b-b9af-01b90427cb38" xlink:to="loc_iart_OptionToExtendLeaseYears_afdc879e-13ab-450f-9455-2087939b7a15" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseOptionToExtend_38042fa6-164f-44f3-abc5-4d7dbe209d58" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseOptionToExtend"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_b2daefe7-aba0-4e9b-b9af-01b90427cb38" xlink:to="loc_us-gaap_LesseeOperatingLeaseOptionToExtend_38042fa6-164f-44f3-abc5-4d7dbe209d58" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/LEASESANDRELATEDPARTYLEASESSupplementalBalanceSheetInformationDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#LEASESANDRELATEDPARTYLEASESSupplementalBalanceSheetInformationDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/LEASESANDRELATEDPARTYLEASESSupplementalBalanceSheetInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_66c7a21a-6ef1-47ac-be8b-d52f2be9b6dc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_60dcaecf-0f87-4b63-be13-2e0ffd314439" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_66c7a21a-6ef1-47ac-be8b-d52f2be9b6dc" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_60dcaecf-0f87-4b63-be13-2e0ffd314439" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_2be5cf22-3d40-40ec-8089-89e07d7e6bc2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_60dcaecf-0f87-4b63-be13-2e0ffd314439" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_2be5cf22-3d40-40ec-8089-89e07d7e6bc2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_2be5cf22-3d40-40ec-8089-89e07d7e6bc2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_2be5cf22-3d40-40ec-8089-89e07d7e6bc2" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_2be5cf22-3d40-40ec-8089-89e07d7e6bc2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6ef1daab-1d01-4fa1-81f0-81d8906adbdb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_2be5cf22-3d40-40ec-8089-89e07d7e6bc2" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6ef1daab-1d01-4fa1-81f0-81d8906adbdb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingMember_1563ff86-8c6b-42bd-bdc5-9ec4b6b5fbda" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BuildingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6ef1daab-1d01-4fa1-81f0-81d8906adbdb" xlink:to="loc_us-gaap_BuildingMember_1563ff86-8c6b-42bd-bdc5-9ec4b6b5fbda" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VehiclesMember_1c4e2aae-0f9f-4b32-b09b-4d6a88f8e1ff" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VehiclesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6ef1daab-1d01-4fa1-81f0-81d8906adbdb" xlink:to="loc_us-gaap_VehiclesMember_1c4e2aae-0f9f-4b32-b09b-4d6a88f8e1ff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_5359efb9-655a-4093-8a38-48216f5468b0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_66c7a21a-6ef1-47ac-be8b-d52f2be9b6dc" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_5359efb9-655a-4093-8a38-48216f5468b0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent_ef76b778-8d0d-4443-b085-e7af93f1a44e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_66c7a21a-6ef1-47ac-be8b-d52f2be9b6dc" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrent_ef76b778-8d0d-4443-b085-e7af93f1a44e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_ca412c20-bc5b-4806-83ea-6a56896c17d8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_66c7a21a-6ef1-47ac-be8b-d52f2be9b6dc" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_ca412c20-bc5b-4806-83ea-6a56896c17d8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_774e0019-01c8-465b-8233-7dfa68022846" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_66c7a21a-6ef1-47ac-be8b-d52f2be9b6dc" xlink:to="loc_us-gaap_OperatingLeaseLiability_774e0019-01c8-465b-8233-7dfa68022846" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_88b7fe2f-7a6c-4ace-a03e-95bf0713fc1c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_66c7a21a-6ef1-47ac-be8b-d52f2be9b6dc" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_88b7fe2f-7a6c-4ace-a03e-95bf0713fc1c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_e26c6d71-f8f6-4b4c-b1e5-bec3d72c2834" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_66c7a21a-6ef1-47ac-be8b-d52f2be9b6dc" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_e26c6d71-f8f6-4b4c-b1e5-bec3d72c2834" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/LEASESANDRELATEDPARTYLEASESFutureMinimumLeasePaymentUnderOperatingLeasesDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#LEASESANDRELATEDPARTYLEASESFutureMinimumLeasePaymentUnderOperatingLeasesDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/LEASESANDRELATEDPARTYLEASESFutureMinimumLeasePaymentUnderOperatingLeasesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeasedAssetsLineItems_3c8e2986-c8c3-48c5-9173-4aa1aa11bf70" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeasedAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfOperatingLeasedAssetsTable_08c942e4-8f56-455b-a593-6d6a2d2a0b30" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfOperatingLeasedAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_3c8e2986-c8c3-48c5-9173-4aa1aa11bf70" xlink:to="loc_us-gaap_ScheduleOfOperatingLeasedAssetsTable_08c942e4-8f56-455b-a593-6d6a2d2a0b30" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_a5be5413-18ed-4e12-848d-a331f0d1d7a7" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfOperatingLeasedAssetsTable_08c942e4-8f56-455b-a593-6d6a2d2a0b30" xlink:to="loc_srt_CounterpartyNameAxis_a5be5413-18ed-4e12-848d-a331f0d1d7a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_a5be5413-18ed-4e12-848d-a331f0d1d7a7_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_a5be5413-18ed-4e12-848d-a331f0d1d7a7" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_a5be5413-18ed-4e12-848d-a331f0d1d7a7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_485fc813-5c05-40f5-a1c9-22f402e00cb7" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_a5be5413-18ed-4e12-848d-a331f0d1d7a7" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_485fc813-5c05-40f5-a1c9-22f402e00cb7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_RelatedPartiesMember_5f5a644b-03b7-43a2-9efc-4a132f9990c7" xlink:href="iart-20250930.xsd#iart_RelatedPartiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_485fc813-5c05-40f5-a1c9-22f402e00cb7" xlink:to="loc_iart_RelatedPartiesMember_5f5a644b-03b7-43a2-9efc-4a132f9990c7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_ThirdPartiesMember_f69f27e5-b683-4f8b-8f8f-8bb2f0cd9a74" xlink:href="iart-20250930.xsd#iart_ThirdPartiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_485fc813-5c05-40f5-a1c9-22f402e00cb7" xlink:to="loc_iart_ThirdPartiesMember_f69f27e5-b683-4f8b-8f8f-8bb2f0cd9a74" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_ef14c99b-8e2d-402a-92da-702a95d668a0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_3c8e2986-c8c3-48c5-9173-4aa1aa11bf70" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_ef14c99b-8e2d-402a-92da-702a95d668a0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_cff65c5d-04cf-458d-9e99-a75aeffe9943" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_3c8e2986-c8c3-48c5-9173-4aa1aa11bf70" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_cff65c5d-04cf-458d-9e99-a75aeffe9943" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_0990ee87-982a-4c60-9839-c82b2faf9bfb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_3c8e2986-c8c3-48c5-9173-4aa1aa11bf70" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_0990ee87-982a-4c60-9839-c82b2faf9bfb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_8a78616d-dd5f-48fa-88ed-3085afc7e00b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_3c8e2986-c8c3-48c5-9173-4aa1aa11bf70" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_8a78616d-dd5f-48fa-88ed-3085afc7e00b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_74547734-d724-4680-b3a9-66cfa4368863" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_3c8e2986-c8c3-48c5-9173-4aa1aa11bf70" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_74547734-d724-4680-b3a9-66cfa4368863" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_38ffcccf-c524-4618-a367-384e7b20006c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_3c8e2986-c8c3-48c5-9173-4aa1aa11bf70" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_38ffcccf-c524-4618-a367-384e7b20006c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_34091ce8-b4d2-4f16-809a-a50fe9d29797" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_3c8e2986-c8c3-48c5-9173-4aa1aa11bf70" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_34091ce8-b4d2-4f16-809a-a50fe9d29797" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_54946f3a-aefa-4d54-a25e-43b399e15931" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_3c8e2986-c8c3-48c5-9173-4aa1aa11bf70" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_54946f3a-aefa-4d54-a25e-43b399e15931" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_de0bb852-4c18-4642-acda-1638ea83d476" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_3c8e2986-c8c3-48c5-9173-4aa1aa11bf70" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_de0bb852-4c18-4642-acda-1638ea83d476" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_dd3ea4fb-46f8-49bd-9bde-cbc0ba2c4f97" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_3c8e2986-c8c3-48c5-9173-4aa1aa11bf70" xlink:to="loc_us-gaap_OperatingLeaseLiability_dd3ea4fb-46f8-49bd-9bde-cbc0ba2c4f97" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent_beced619-82a0-41e8-8c63-1eaf75cd480d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_3c8e2986-c8c3-48c5-9173-4aa1aa11bf70" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrent_beced619-82a0-41e8-8c63-1eaf75cd480d" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_136128b1-8134-437f-b183-833380a41f29" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeasedAssetsLineItems_3c8e2986-c8c3-48c5-9173-4aa1aa11bf70" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_136128b1-8134-437f-b183-833380a41f29" xlink:type="arc" order="11"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/TREASURYSTOCKDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#TREASURYSTOCKDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/TREASURYSTOCKDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_fc1b5cca-4f22-44a2-833e-4cda076793e2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_1f88e0ec-339a-489d-9b67-be29da23bdb9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_fc1b5cca-4f22-44a2-833e-4cda076793e2" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_1f88e0ec-339a-489d-9b67-be29da23bdb9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ShareRepurchaseProgramAxis_61f5b987-d07b-460a-bded-244cd81bff08" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ShareRepurchaseProgramAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_1f88e0ec-339a-489d-9b67-be29da23bdb9" xlink:to="loc_srt_ShareRepurchaseProgramAxis_61f5b987-d07b-460a-bded-244cd81bff08" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ShareRepurchaseProgramDomain_61f5b987-d07b-460a-bded-244cd81bff08_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ShareRepurchaseProgramDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ShareRepurchaseProgramAxis_61f5b987-d07b-460a-bded-244cd81bff08" xlink:to="loc_srt_ShareRepurchaseProgramDomain_61f5b987-d07b-460a-bded-244cd81bff08_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ShareRepurchaseProgramDomain_28543d4a-4cef-43d9-888e-f05a58a0e738" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ShareRepurchaseProgramDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ShareRepurchaseProgramAxis_61f5b987-d07b-460a-bded-244cd81bff08" xlink:to="loc_srt_ShareRepurchaseProgramDomain_28543d4a-4cef-43d9-888e-f05a58a0e738" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_A2023ShareRepurchaseProgramMember_355ad312-3ded-47b3-963c-712ab5cf9084" xlink:href="iart-20250930.xsd#iart_A2023ShareRepurchaseProgramMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ShareRepurchaseProgramDomain_28543d4a-4cef-43d9-888e-f05a58a0e738" xlink:to="loc_iart_A2023ShareRepurchaseProgramMember_355ad312-3ded-47b3-963c-712ab5cf9084" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_e2c1e6bf-cb9c-4d17-b6be-8cfd22d2cf4c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockCommonShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_fc1b5cca-4f22-44a2-833e-4cda076793e2" xlink:to="loc_us-gaap_TreasuryStockCommonShares_e2c1e6bf-cb9c-4d17-b6be-8cfd22d2cf4c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonValue_a3d3e80a-4340-4e18-8e2a-cfb5b153b6a9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockCommonValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_fc1b5cca-4f22-44a2-833e-4cda076793e2" xlink:to="loc_us-gaap_TreasuryStockCommonValue_a3d3e80a-4340-4e18-8e2a-cfb5b153b6a9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockAcquiredAverageCostPerShare_e1cb536b-86e9-4f3b-a1d1-f822aceeed42" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockAcquiredAverageCostPerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_fc1b5cca-4f22-44a2-833e-4cda076793e2" xlink:to="loc_us-gaap_TreasuryStockAcquiredAverageCostPerShare_e1cb536b-86e9-4f3b-a1d1-f822aceeed42" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcceleratedShareRepurchasesSettlementPaymentOrReceipt_7e62c6c7-f170-4a5d-89e2-e934824c59fc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AcceleratedShareRepurchasesSettlementPaymentOrReceipt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_fc1b5cca-4f22-44a2-833e-4cda076793e2" xlink:to="loc_us-gaap_AcceleratedShareRepurchasesSettlementPaymentOrReceipt_7e62c6c7-f170-4a5d-89e2-e934824c59fc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_AcceleratedShareRepurchasesSharesReceivedAtInception_8756fcc0-b9c7-4a6b-bc44-686b67ebe8a9" xlink:href="iart-20250930.xsd#iart_AcceleratedShareRepurchasesSharesReceivedAtInception"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_fc1b5cca-4f22-44a2-833e-4cda076793e2" xlink:to="loc_iart_AcceleratedShareRepurchasesSharesReceivedAtInception_8756fcc0-b9c7-4a6b-bc44-686b67ebe8a9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_AcceleratedShareRepurchasesPercentageOfExpectedTotalRepurchased_19fd899b-c162-486e-bb78-849e42b37291" xlink:href="iart-20250930.xsd#iart_AcceleratedShareRepurchasesPercentageOfExpectedTotalRepurchased"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_fc1b5cca-4f22-44a2-833e-4cda076793e2" xlink:to="loc_iart_AcceleratedShareRepurchasesPercentageOfExpectedTotalRepurchased_19fd899b-c162-486e-bb78-849e42b37291" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_AcceleratedShareRepurchasesAdditionalSharesReceived_c1712644-c0c8-4ba5-a062-238a476b9841" xlink:href="iart-20250930.xsd#iart_AcceleratedShareRepurchasesAdditionalSharesReceived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_fc1b5cca-4f22-44a2-833e-4cda076793e2" xlink:to="loc_iart_AcceleratedShareRepurchasesAdditionalSharesReceived_c1712644-c0c8-4ba5-a062-238a476b9841" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StockRepurchaseProgramAuthorizedAmount1_3c08c262-3052-43cd-b7c8-fb813efdf463" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_StockRepurchaseProgramAuthorizedAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_fc1b5cca-4f22-44a2-833e-4cda076793e2" xlink:to="loc_srt_StockRepurchaseProgramAuthorizedAmount1_3c08c262-3052-43cd-b7c8-fb813efdf463" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_3c1aa2dd-f9f6-4844-b21a-35e9c6eab158" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_fc1b5cca-4f22-44a2-833e-4cda076793e2" xlink:to="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_3c1aa2dd-f9f6-4844-b21a-35e9c6eab158" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/INCOMETAXESNarrativeDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#INCOMETAXESNarrativeDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/INCOMETAXESNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationLineItems_551c59bd-799d-4aeb-b4d3-c914fd7fadcf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationTable_e841e30a-8db8-4787-a753-9b59a83aeff6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationLineItems_551c59bd-799d-4aeb-b4d3-c914fd7fadcf" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateReconciliationTable_e841e30a-8db8-4787-a753-9b59a83aeff6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementScenarioAxis_84d9c932-408b-4f1f-bc95-98372230a304" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_StatementScenarioAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationTable_e841e30a-8db8-4787-a753-9b59a83aeff6" xlink:to="loc_srt_StatementScenarioAxis_84d9c932-408b-4f1f-bc95-98372230a304" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_84d9c932-408b-4f1f-bc95-98372230a304_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_84d9c932-408b-4f1f-bc95-98372230a304" xlink:to="loc_srt_ScenarioUnspecifiedDomain_84d9c932-408b-4f1f-bc95-98372230a304_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_ff820c3b-b57d-47f2-9d94-1591352b0efe" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_84d9c932-408b-4f1f-bc95-98372230a304" xlink:to="loc_srt_ScenarioUnspecifiedDomain_ff820c3b-b57d-47f2-9d94-1591352b0efe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioForecastMember_a62aae4d-7f85-4982-a39b-6d6e6cc08206" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ScenarioForecastMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_ff820c3b-b57d-47f2-9d94-1591352b0efe" xlink:to="loc_srt_ScenarioForecastMember_a62aae4d-7f85-4982-a39b-6d6e6cc08206" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations_21a9747a-4e59-44fa-8075-cec5c047ebfc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationLineItems_551c59bd-799d-4aeb-b4d3-c914fd7fadcf" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations_21a9747a-4e59-44fa-8075-cec5c047ebfc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxReconciliationPriorYearIncomeTaxes_873e8f42-37b8-4646-803d-cca1fe176976" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxReconciliationPriorYearIncomeTaxes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationLineItems_551c59bd-799d-4aeb-b4d3-c914fd7fadcf" xlink:to="loc_us-gaap_IncomeTaxReconciliationPriorYearIncomeTaxes_873e8f42-37b8-4646-803d-cca1fe176976" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_IncomeTaxReconciliationOneBigBeautifulBillActAmount_e9aecd68-7e4d-4077-9050-b1b08f396695" xlink:href="iart-20250930.xsd#iart_IncomeTaxReconciliationOneBigBeautifulBillActAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EffectiveIncomeTaxRateReconciliationLineItems_551c59bd-799d-4aeb-b4d3-c914fd7fadcf" xlink:to="loc_iart_IncomeTaxReconciliationOneBigBeautifulBillActAmount_e9aecd68-7e4d-4077-9050-b1b08f396695" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSSScheduleofChangesinAccumulatedOtherComprehensiveIncomeLossbyComponentDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#ACCUMULATEDOTHERCOMPREHENSIVELOSSScheduleofChangesinAccumulatedOtherComprehensiveIncomeLossbyComponentDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSSScheduleofChangesinAccumulatedOtherComprehensiveIncomeLossbyComponentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_964a94d3-5f2e-4a2f-bc1e-7ed6676ca3e9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_5b2d2b8b-731b-4e47-aa95-93a6b85ca961" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_964a94d3-5f2e-4a2f-bc1e-7ed6676ca3e9" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_5b2d2b8b-731b-4e47-aa95-93a6b85ca961" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_2acd176c-2324-4234-bec1-285312952f16" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_5b2d2b8b-731b-4e47-aa95-93a6b85ca961" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_2acd176c-2324-4234-bec1-285312952f16" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_2acd176c-2324-4234-bec1-285312952f16_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_2acd176c-2324-4234-bec1-285312952f16" xlink:to="loc_us-gaap_EquityComponentDomain_2acd176c-2324-4234-bec1-285312952f16_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_292e56de-1651-4a1f-9eed-26736ceaf66a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_2acd176c-2324-4234-bec1-285312952f16" xlink:to="loc_us-gaap_EquityComponentDomain_292e56de-1651-4a1f-9eed-26736ceaf66a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_5bbe5306-9c73-4ef1-9c8e-53c6df73dbb0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_292e56de-1651-4a1f-9eed-26736ceaf66a" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_5bbe5306-9c73-4ef1-9c8e-53c6df73dbb0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_23074769-fb3f-43ca-978f-6ef34fac8e63" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_5bbe5306-9c73-4ef1-9c8e-53c6df73dbb0" xlink:to="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_23074769-fb3f-43ca-978f-6ef34fac8e63" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_30c4afaa-7c55-4953-884f-3ac00afb6a3c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_5bbe5306-9c73-4ef1-9c8e-53c6df73dbb0" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_30c4afaa-7c55-4953-884f-3ac00afb6a3c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_117e3856-b643-45e6-8145-578bd9bbddbe" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedTranslationAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_5bbe5306-9c73-4ef1-9c8e-53c6df73dbb0" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_117e3856-b643-45e6-8145-578bd9bbddbe" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_90016958-08e8-4735-85bc-659e433071bc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AOCIAttributableToParentNetOfTaxRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_964a94d3-5f2e-4a2f-bc1e-7ed6676ca3e9" xlink:to="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_90016958-08e8-4735-85bc-659e433071bc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_df49c9b9-74b4-4668-8357-32ae804d723e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_90016958-08e8-4735-85bc-659e433071bc" xlink:to="loc_us-gaap_StockholdersEquity_df49c9b9-74b4-4668-8357-32ae804d723e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent_e41f0d88-6958-4434-9128-922c46576cb1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_90016958-08e8-4735-85bc-659e433071bc" xlink:to="loc_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent_e41f0d88-6958-4434-9128-922c46576cb1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_6f763d81-3f26-4569-b46d-00c40a9cd2ff" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_90016958-08e8-4735-85bc-659e433071bc" xlink:to="loc_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_6f763d81-3f26-4569-b46d-00c40a9cd2ff" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_cf541544-79d1-4cbf-b5ba-2eb45a306597" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_90016958-08e8-4735-85bc-659e433071bc" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_cf541544-79d1-4cbf-b5ba-2eb45a306597" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_ede3f549-2957-4490-a6d4-d9ae47bc23c5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSSNarrativeDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#ACCUMULATEDOTHERCOMPREHENSIVELOSSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/ACCUMULATEDOTHERCOMPREHENSIVELOSSNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_260ba4ae-85e1-4981-8e55-bc7fcfca4263" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_1c727116-0948-43b5-9ad9-eb40ecfbc52b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_260ba4ae-85e1-4981-8e55-bc7fcfca4263" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_1c727116-0948-43b5-9ad9-eb40ecfbc52b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_2dcb9ce4-b490-4d57-8f74-e68efcded0b0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_1c727116-0948-43b5-9ad9-eb40ecfbc52b" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_2dcb9ce4-b490-4d57-8f74-e68efcded0b0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_2dcb9ce4-b490-4d57-8f74-e68efcded0b0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_2dcb9ce4-b490-4d57-8f74-e68efcded0b0" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_2dcb9ce4-b490-4d57-8f74-e68efcded0b0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_84e22d58-0e28-41ae-b309-3fbbd787daf0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_2dcb9ce4-b490-4d57-8f74-e68efcded0b0" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_84e22d58-0e28-41ae-b309-3fbbd787daf0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpenseMember_b54fc221-5b72-4ec2-ac37-8e72942caea3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherNonoperatingIncomeExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_84e22d58-0e28-41ae-b309-3fbbd787daf0" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpenseMember_b54fc221-5b72-4ec2-ac37-8e72942caea3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfSalesMember_c951d97c-614b-406d-9ccd-bf923d98878a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostOfSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_84e22d58-0e28-41ae-b309-3fbbd787daf0" xlink:to="loc_us-gaap_CostOfSalesMember_c951d97c-614b-406d-9ccd-bf923d98878a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeMember_2bd6eab4-2cf0-4677-8d0d-ed52980355ce" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_84e22d58-0e28-41ae-b309-3fbbd787daf0" xlink:to="loc_us-gaap_InterestIncomeMember_2bd6eab4-2cf0-4677-8d0d-ed52980355ce" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_9f71e1c3-e658-4407-a048-cf45d41224a0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_1c727116-0948-43b5-9ad9-eb40ecfbc52b" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_9f71e1c3-e658-4407-a048-cf45d41224a0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_9f71e1c3-e658-4407-a048-cf45d41224a0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_9f71e1c3-e658-4407-a048-cf45d41224a0" xlink:to="loc_us-gaap_EquityComponentDomain_9f71e1c3-e658-4407-a048-cf45d41224a0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_8133c8ec-c0b5-4755-a7a7-10217a803902" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_9f71e1c3-e658-4407-a048-cf45d41224a0" xlink:to="loc_us-gaap_EquityComponentDomain_8133c8ec-c0b5-4755-a7a7-10217a803902" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_6dc17b1c-3c9b-45fb-969a-eef99a536e1c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_8133c8ec-c0b5-4755-a7a7-10217a803902" xlink:to="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_6dc17b1c-3c9b-45fb-969a-eef99a536e1c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_52972e63-44ab-4c25-b374-69f8620ef1d1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_260ba4ae-85e1-4981-8e55-bc7fcfca4263" xlink:to="loc_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_52972e63-44ab-4c25-b374-69f8620ef1d1" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/SEGMENTANDGEOGRAPHICINFORMATIONNarrativeDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#SEGMENTANDGEOGRAPHICINFORMATIONNarrativeDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/SEGMENTANDGEOGRAPHICINFORMATIONNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_9f3f2839-61a8-4f3e-9c9d-f52e9caca2bb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_a19f46f2-84af-4953-a3c6-cc24ce8a05b9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_9f3f2839-61a8-4f3e-9c9d-f52e9caca2bb" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_a19f46f2-84af-4953-a3c6-cc24ce8a05b9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_7a58de4c-4b9a-4af2-816b-f94a3f4e8af3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_a19f46f2-84af-4953-a3c6-cc24ce8a05b9" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_7a58de4c-4b9a-4af2-816b-f94a3f4e8af3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_7a58de4c-4b9a-4af2-816b-f94a3f4e8af3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_7a58de4c-4b9a-4af2-816b-f94a3f4e8af3" xlink:to="loc_us-gaap_SegmentDomain_7a58de4c-4b9a-4af2-816b-f94a3f4e8af3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_88837df3-c657-48a7-8f27-2400e5565cc0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_7a58de4c-4b9a-4af2-816b-f94a3f4e8af3" xlink:to="loc_us-gaap_SegmentDomain_88837df3-c657-48a7-8f27-2400e5565cc0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CodmanSpecialtySurgicalMember_8a379932-a192-4b5c-a730-eac8d0d8dd1e" xlink:href="iart-20250930.xsd#iart_CodmanSpecialtySurgicalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_88837df3-c657-48a7-8f27-2400e5565cc0" xlink:to="loc_iart_CodmanSpecialtySurgicalMember_8a379932-a192-4b5c-a730-eac8d0d8dd1e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments_1bed2ff8-f0f5-4e9d-98f8-cf0cae6927e1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NumberOfReportableSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_9f3f2839-61a8-4f3e-9c9d-f52e9caca2bb" xlink:to="loc_us-gaap_NumberOfReportableSegments_1bed2ff8-f0f5-4e9d-98f8-cf0cae6927e1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_SegmentReportingInformationNumberOfProductsOffered_f991b8f7-a801-4a79-888c-fa8312ff2eff" xlink:href="iart-20250930.xsd#iart_SegmentReportingInformationNumberOfProductsOffered"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_9f3f2839-61a8-4f3e-9c9d-f52e9caca2bb" xlink:to="loc_iart_SegmentReportingInformationNumberOfProductsOffered_f991b8f7-a801-4a79-888c-fa8312ff2eff" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/SEGMENTANDGEOGRAPHICINFORMATIONSegmentReportingInformationDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#SEGMENTANDGEOGRAPHICINFORMATIONSegmentReportingInformationDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/SEGMENTANDGEOGRAPHICINFORMATIONSegmentReportingInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_714bbc0e-2f54-4ea6-be7c-326a94b53c6d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_df36ebb1-ccea-482a-8e05-26b3171276aa" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_714bbc0e-2f54-4ea6-be7c-326a94b53c6d" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_df36ebb1-ccea-482a-8e05-26b3171276aa" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_3a654f97-b455-417e-be30-4a985c28c767" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_df36ebb1-ccea-482a-8e05-26b3171276aa" xlink:to="loc_srt_ConsolidationItemsAxis_3a654f97-b455-417e-be30-4a985c28c767" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_3a654f97-b455-417e-be30-4a985c28c767_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_3a654f97-b455-417e-be30-4a985c28c767" xlink:to="loc_srt_ConsolidationItemsDomain_3a654f97-b455-417e-be30-4a985c28c767_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_71731c4b-2042-4e4b-b47d-8d7a814ab984" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_3a654f97-b455-417e-be30-4a985c28c767" xlink:to="loc_srt_ConsolidationItemsDomain_71731c4b-2042-4e4b-b47d-8d7a814ab984" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_72d60e26-d5fa-4ab6-b9f3-566da1941ae8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_71731c4b-2042-4e4b-b47d-8d7a814ab984" xlink:to="loc_us-gaap_OperatingSegmentsMember_72d60e26-d5fa-4ab6-b9f3-566da1941ae8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_274c04b4-ef03-42ec-afdb-5f20dc9c402a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_71731c4b-2042-4e4b-b47d-8d7a814ab984" xlink:to="loc_us-gaap_CorporateNonSegmentMember_274c04b4-ef03-42ec-afdb-5f20dc9c402a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_4978b936-5703-45cf-ae82-1cee3f241b65" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_df36ebb1-ccea-482a-8e05-26b3171276aa" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_4978b936-5703-45cf-ae82-1cee3f241b65" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_4978b936-5703-45cf-ae82-1cee3f241b65_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_4978b936-5703-45cf-ae82-1cee3f241b65" xlink:to="loc_us-gaap_SegmentDomain_4978b936-5703-45cf-ae82-1cee3f241b65_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_19fdd31b-766d-4101-acc9-2cece72115dd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_4978b936-5703-45cf-ae82-1cee3f241b65" xlink:to="loc_us-gaap_SegmentDomain_19fdd31b-766d-4101-acc9-2cece72115dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CodmanSpecialtySurgicalMember_493be43c-8ad1-42e2-a301-0f4006071bbf" xlink:href="iart-20250930.xsd#iart_CodmanSpecialtySurgicalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_19fdd31b-766d-4101-acc9-2cece72115dd" xlink:to="loc_iart_CodmanSpecialtySurgicalMember_493be43c-8ad1-42e2-a301-0f4006071bbf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_TissueTechnologiesMember_eb9fe510-2f1e-44f8-be56-631c4578e620" xlink:href="iart-20250930.xsd#iart_TissueTechnologiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_19fdd31b-766d-4101-acc9-2cece72115dd" xlink:to="loc_iart_TissueTechnologiesMember_eb9fe510-2f1e-44f8-be56-631c4578e620" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_4b4ba3b5-22cf-41c6-8562-1723c2fa2b22" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_714bbc0e-2f54-4ea6-be7c-326a94b53c6d" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_4b4ba3b5-22cf-41c6-8562-1723c2fa2b22" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_fd3eb21a-a980-4456-a018-b3e6b9611a56" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_714bbc0e-2f54-4ea6-be7c-326a94b53c6d" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_fd3eb21a-a980-4456-a018-b3e6b9611a56" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseExcludingAcquiredInProcessCost_dcdd6044-d9da-4d98-888c-780cb6ea36e1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ResearchAndDevelopmentExpenseExcludingAcquiredInProcessCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_714bbc0e-2f54-4ea6-be7c-326a94b53c6d" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseExcludingAcquiredInProcessCost_dcdd6044-d9da-4d98-888c-780cb6ea36e1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_a063af53-07cf-4cf9-aa1b-98465b44a2c1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_714bbc0e-2f54-4ea6-be7c-326a94b53c6d" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_a063af53-07cf-4cf9-aa1b-98465b44a2c1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_7df14df5-472b-4387-8d9a-69421fab9aeb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_714bbc0e-2f54-4ea6-be7c-326a94b53c6d" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_7df14df5-472b-4387-8d9a-69421fab9aeb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_3a8f3d34-1617-47b6-8a78-bdc99d0b29d7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_714bbc0e-2f54-4ea6-be7c-326a94b53c6d" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_3a8f3d34-1617-47b6-8a78-bdc99d0b29d7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpenses_b02695b3-2540-4f65-85ab-90b099c96949" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostsAndExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_714bbc0e-2f54-4ea6-be7c-326a94b53c6d" xlink:to="loc_us-gaap_CostsAndExpenses_b02695b3-2540-4f65-85ab-90b099c96949" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_bcac2979-a4c1-4931-bdd5-00df2b722be8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_714bbc0e-2f54-4ea6-be7c-326a94b53c6d" xlink:to="loc_us-gaap_OperatingIncomeLoss_bcac2979-a4c1-4931-bdd5-00df2b722be8" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeInterest_24b4ea4d-c8fe-40fb-bbde-be810705c099" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InvestmentIncomeInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_714bbc0e-2f54-4ea6-be7c-326a94b53c6d" xlink:to="loc_us-gaap_InvestmentIncomeInterest_24b4ea4d-c8fe-40fb-bbde-be810705c099" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseNonoperating_470fd6c1-2610-41a6-a38c-3c8871d7280b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestExpenseNonoperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_714bbc0e-2f54-4ea6-be7c-326a94b53c6d" xlink:to="loc_us-gaap_InterestExpenseNonoperating_470fd6c1-2610-41a6-a38c-3c8871d7280b" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_226276b6-75af-4f7a-bcee-00500cc5b1fc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_714bbc0e-2f54-4ea6-be7c-326a94b53c6d" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_226276b6-75af-4f7a-bcee-00500cc5b1fc" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_1b947266-8646-4fca-a98a-dff16d44b1c6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_714bbc0e-2f54-4ea6-be7c-326a94b53c6d" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_1b947266-8646-4fca-a98a-dff16d44b1c6" xlink:type="arc" order="11"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/SEGMENTANDGEOGRAPHICINFORMATIONRevenuebyMajorGeographicAreaDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#SEGMENTANDGEOGRAPHICINFORMATIONRevenuebyMajorGeographicAreaDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/SEGMENTANDGEOGRAPHICINFORMATIONRevenuebyMajorGeographicAreaDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_d1d6ab44-2e88-4bab-9928-864a7735d649" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_3ce2eb42-c9a1-40ee-9400-ea579919adf2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_d1d6ab44-2e88-4bab-9928-864a7735d649" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_3ce2eb42-c9a1-40ee-9400-ea579919adf2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_083e3bf1-4386-43e5-b29e-8cd705a15d7b" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_3ce2eb42-c9a1-40ee-9400-ea579919adf2" xlink:to="loc_srt_StatementGeographicalAxis_083e3bf1-4386-43e5-b29e-8cd705a15d7b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_083e3bf1-4386-43e5-b29e-8cd705a15d7b_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_083e3bf1-4386-43e5-b29e-8cd705a15d7b" xlink:to="loc_srt_SegmentGeographicalDomain_083e3bf1-4386-43e5-b29e-8cd705a15d7b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_759d7569-8f5e-4a87-9732-bbdd7e17a51b" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_083e3bf1-4386-43e5-b29e-8cd705a15d7b" xlink:to="loc_srt_SegmentGeographicalDomain_759d7569-8f5e-4a87-9732-bbdd7e17a51b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_6fb96473-656b-46b0-b27a-172232290f1b" xlink:href="https://xbrl.sec.gov/country/2025/country-2025.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_759d7569-8f5e-4a87-9732-bbdd7e17a51b" xlink:to="loc_country_US_6fb96473-656b-46b0-b27a-172232290f1b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EuropeMember_a22588fb-c02f-4634-a78a-df6d29ea86db" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_EuropeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_759d7569-8f5e-4a87-9732-bbdd7e17a51b" xlink:to="loc_srt_EuropeMember_a22588fb-c02f-4634-a78a-df6d29ea86db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaPacificMember_e8ec2251-93be-4827-a03c-ed0714fe3f9c" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_AsiaPacificMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_759d7569-8f5e-4a87-9732-bbdd7e17a51b" xlink:to="loc_srt_AsiaPacificMember_e8ec2251-93be-4827-a03c-ed0714fe3f9c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_RestOfTheWorldMember_3fff2343-e329-45ae-84c4-1a86ece914b3" xlink:href="iart-20250930.xsd#iart_RestOfTheWorldMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_759d7569-8f5e-4a87-9732-bbdd7e17a51b" xlink:to="loc_iart_RestOfTheWorldMember_3fff2343-e329-45ae-84c4-1a86ece914b3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_f249de78-8cdd-4628-9f13-ee3fe4591417" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_d1d6ab44-2e88-4bab-9928-864a7735d649" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_f249de78-8cdd-4628-9f13-ee3fe4591417" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/COMMITMENTSANDCONTINGENCIESFairValueContingentConsiderationDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#COMMITMENTSANDCONTINGENCIESFairValueContingentConsiderationDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/COMMITMENTSANDCONTINGENCIESFairValueContingentConsiderationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_b325720b-8421-4be4-957e-1ecc430e029c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_8f9e1e33-148b-42e2-a8fd-91a56ca39b3a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_b325720b-8421-4be4-957e-1ecc430e029c" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_8f9e1e33-148b-42e2-a8fd-91a56ca39b3a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_19c08d5e-e2d5-486a-abc8-e39c5667a0b9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_8f9e1e33-148b-42e2-a8fd-91a56ca39b3a" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_19c08d5e-e2d5-486a-abc8-e39c5667a0b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_19c08d5e-e2d5-486a-abc8-e39c5667a0b9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_19c08d5e-e2d5-486a-abc8-e39c5667a0b9" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_19c08d5e-e2d5-486a-abc8-e39c5667a0b9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_acde4987-3d9e-4407-8ea2-a35b620022f1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_19c08d5e-e2d5-486a-abc8-e39c5667a0b9" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_acde4987-3d9e-4407-8ea2-a35b620022f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_ArkisBioSciencesInc.Member_68885397-d5ca-42dd-a2e1-39adde40ac22" xlink:href="iart-20250930.xsd#iart_ArkisBioSciencesInc.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_acde4987-3d9e-4407-8ea2-a35b620022f1" xlink:to="loc_iart_ArkisBioSciencesInc.Member_68885397-d5ca-42dd-a2e1-39adde40ac22" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DermaSciencesMember_5ce062b1-260f-4cee-a9c4-630f8a77da3a" xlink:href="iart-20250930.xsd#iart_DermaSciencesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_acde4987-3d9e-4407-8ea2-a35b620022f1" xlink:to="loc_iart_DermaSciencesMember_5ce062b1-260f-4cee-a9c4-630f8a77da3a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_ACellMember_c99b7406-c86b-4527-8d29-8bbc5d5de0f3" xlink:href="iart-20250930.xsd#iart_ACellMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_acde4987-3d9e-4407-8ea2-a35b620022f1" xlink:to="loc_iart_ACellMember_c99b7406-c86b-4527-8d29-8bbc5d5de0f3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_SurgicalInnovationAssociatesIncMember_6d411519-27ce-4b34-842c-4b5a0adf2a82" xlink:href="iart-20250930.xsd#iart_SurgicalInnovationAssociatesIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_acde4987-3d9e-4407-8ea2-a35b620022f1" xlink:to="loc_iart_SurgicalInnovationAssociatesIncMember_6d411519-27ce-4b34-842c-4b5a0adf2a82" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByLiabilityClassAxis_899f4b41-61ba-4e94-b4e2-fa98c879b90d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByLiabilityClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_8f9e1e33-148b-42e2-a8fd-91a56ca39b3a" xlink:to="loc_us-gaap_FairValueByLiabilityClassAxis_899f4b41-61ba-4e94-b4e2-fa98c879b90d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_899f4b41-61ba-4e94-b4e2-fa98c879b90d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_899f4b41-61ba-4e94-b4e2-fa98c879b90d" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_899f4b41-61ba-4e94-b4e2-fa98c879b90d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_505ff7e7-32cd-423f-8520-4c141a05242e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByLiabilityClassAxis_899f4b41-61ba-4e94-b4e2-fa98c879b90d" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_505ff7e7-32cd-423f-8520-4c141a05242e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_ContingentConsiderationLiabilityMember_c4ffbd88-67e6-414c-b2c8-8288f6818009" xlink:href="iart-20250930.xsd#iart_ContingentConsiderationLiabilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByLiabilityClassDomain_505ff7e7-32cd-423f-8520-4c141a05242e" xlink:to="loc_iart_ContingentConsiderationLiabilityMember_c4ffbd88-67e6-414c-b2c8-8288f6818009" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_8b265b3b-80a3-4b36-a033-234d6c5bc530" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_8f9e1e33-148b-42e2-a8fd-91a56ca39b3a" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_8b265b3b-80a3-4b36-a033-234d6c5bc530" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_8b265b3b-80a3-4b36-a033-234d6c5bc530_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_8b265b3b-80a3-4b36-a033-234d6c5bc530" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_8b265b3b-80a3-4b36-a033-234d6c5bc530_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_5ed28407-446d-4da1-a979-3974a4e910fc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_8b265b3b-80a3-4b36-a033-234d6c5bc530" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_5ed28407-446d-4da1-a979-3974a4e910fc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_28298ff2-4b6e-4d34-a420-a3be8da45ffd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_5ed28407-446d-4da1-a979-3974a4e910fc" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_28298ff2-4b6e-4d34-a420-a3be8da45ffd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_21ee942d-d0b5-48a7-ad2b-bff1f1ec7a03" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_8f9e1e33-148b-42e2-a8fd-91a56ca39b3a" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_21ee942d-d0b5-48a7-ad2b-bff1f1ec7a03" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_21ee942d-d0b5-48a7-ad2b-bff1f1ec7a03_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_21ee942d-d0b5-48a7-ad2b-bff1f1ec7a03" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_21ee942d-d0b5-48a7-ad2b-bff1f1ec7a03_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_d10a966e-0812-4bbd-83cd-80eb02f5b21a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_21ee942d-d0b5-48a7-ad2b-bff1f1ec7a03" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_d10a966e-0812-4bbd-83cd-80eb02f5b21a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCurrentLiabilitiesMember_8279341a-90a7-4a82-8f23-82dc11c59758" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherCurrentLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_d10a966e-0812-4bbd-83cd-80eb02f5b21a" xlink:to="loc_us-gaap_OtherCurrentLiabilitiesMember_8279341a-90a7-4a82-8f23-82dc11c59758" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncurrentLiabilitiesMember_892fc99e-49d0-4843-9ca9-fe4de98adb0a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherNoncurrentLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_d10a966e-0812-4bbd-83cd-80eb02f5b21a" xlink:to="loc_us-gaap_OtherNoncurrentLiabilitiesMember_892fc99e-49d0-4843-9ca9-fe4de98adb0a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_af9cb026-e4ce-4c05-bd54-77bbcea7fc6b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_b325720b-8421-4be4-957e-1ecc430e029c" xlink:to="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_af9cb026-e4ce-4c05-bd54-77bbcea7fc6b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_c1dd967c-fcf2-4d46-9ba4-8a134011345f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_af9cb026-e4ce-4c05-bd54-77bbcea7fc6b" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_c1dd967c-fcf2-4d46-9ba4-8a134011345f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements_7700e5b1-205d-4ccd-b1a1-b7f45ee81a54" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_af9cb026-e4ce-4c05-bd54-77bbcea7fc6b" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements_7700e5b1-205d-4ccd-b1a1-b7f45ee81a54" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings_44c062c8-6572-4f47-a012-d75966057e0b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_af9cb026-e4ce-4c05-bd54-77bbcea7fc6b" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings_44c062c8-6572-4f47-a012-d75966057e0b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue_70840ba5-fbb2-447a-8db0-5a52c2b02059" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/COMMITMENTSANDCONTINGENCIESNarrativeDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#COMMITMENTSANDCONTINGENCIESNarrativeDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/COMMITMENTSANDCONTINGENCIESNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_23e855ba-3362-41b9-8802-a7781ba40b89" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_0006e2d6-83ba-41c8-bdd5-7bd25312b85c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_23e855ba-3362-41b9-8802-a7781ba40b89" xlink:to="loc_us-gaap_LossContingenciesTable_0006e2d6-83ba-41c8-bdd5-7bd25312b85c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_201e5c0f-3dde-4cc1-9573-f7aa6e922d2e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_0006e2d6-83ba-41c8-bdd5-7bd25312b85c" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_201e5c0f-3dde-4cc1-9573-f7aa6e922d2e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_201e5c0f-3dde-4cc1-9573-f7aa6e922d2e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_201e5c0f-3dde-4cc1-9573-f7aa6e922d2e" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_201e5c0f-3dde-4cc1-9573-f7aa6e922d2e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_c8a733e9-c9a0-4d76-b7ab-e77b93b4f081" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_201e5c0f-3dde-4cc1-9573-f7aa6e922d2e" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_c8a733e9-c9a0-4d76-b7ab-e77b93b4f081" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_ArkisBioSciencesInc.Member_6f83c94e-a784-47f1-8c58-4e5aeaa4e226" xlink:href="iart-20250930.xsd#iart_ArkisBioSciencesInc.Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_c8a733e9-c9a0-4d76-b7ab-e77b93b4f081" xlink:to="loc_iart_ArkisBioSciencesInc.Member_6f83c94e-a784-47f1-8c58-4e5aeaa4e226" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DermaSciencesMember_ef0d598f-b2e0-4ecb-9a1a-4e673ad3805b" xlink:href="iart-20250930.xsd#iart_DermaSciencesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_c8a733e9-c9a0-4d76-b7ab-e77b93b4f081" xlink:to="loc_iart_DermaSciencesMember_ef0d598f-b2e0-4ecb-9a1a-4e673ad3805b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_ACellIncMember_2e7209e4-6065-4d20-a65a-0df2054e5293" xlink:href="iart-20250930.xsd#iart_ACellIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_c8a733e9-c9a0-4d76-b7ab-e77b93b4f081" xlink:to="loc_iart_ACellIncMember_2e7209e4-6065-4d20-a65a-0df2054e5293" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_SurgicalInnovationAssociatesIncMember_6a505bba-74a4-4d6b-828b-6bee328453c7" xlink:href="iart-20250930.xsd#iart_SurgicalInnovationAssociatesIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_c8a733e9-c9a0-4d76-b7ab-e77b93b4f081" xlink:to="loc_iart_SurgicalInnovationAssociatesIncMember_6a505bba-74a4-4d6b-828b-6bee328453c7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContingentConsiderationByTypeAxis_3cdb3e5c-fa81-491b-9707-dfe5256b1dca" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContingentConsiderationByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_0006e2d6-83ba-41c8-bdd5-7bd25312b85c" xlink:to="loc_us-gaap_ContingentConsiderationByTypeAxis_3cdb3e5c-fa81-491b-9707-dfe5256b1dca" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContingentConsiderationTypeDomain_3cdb3e5c-fa81-491b-9707-dfe5256b1dca_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContingentConsiderationTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContingentConsiderationByTypeAxis_3cdb3e5c-fa81-491b-9707-dfe5256b1dca" xlink:to="loc_us-gaap_ContingentConsiderationTypeDomain_3cdb3e5c-fa81-491b-9707-dfe5256b1dca_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContingentConsiderationTypeDomain_263a72a2-8f95-4faf-b4c6-b44f9cc8217f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContingentConsiderationTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContingentConsiderationByTypeAxis_3cdb3e5c-fa81-491b-9707-dfe5256b1dca" xlink:to="loc_us-gaap_ContingentConsiderationTypeDomain_263a72a2-8f95-4faf-b4c6-b44f9cc8217f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_DevelopmentMilestonesMember_8e6f89b4-ef51-458a-a2ed-67f67d9aef39" xlink:href="iart-20250930.xsd#iart_DevelopmentMilestonesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContingentConsiderationTypeDomain_263a72a2-8f95-4faf-b4c6-b44f9cc8217f" xlink:to="loc_iart_DevelopmentMilestonesMember_8e6f89b4-ef51-458a-a2ed-67f67d9aef39" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_CommercialSalesMilestonesMember_f27e88d7-5f2b-4401-a70a-8c902b4e9365" xlink:href="iart-20250930.xsd#iart_CommercialSalesMilestonesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContingentConsiderationTypeDomain_263a72a2-8f95-4faf-b4c6-b44f9cc8217f" xlink:to="loc_iart_CommercialSalesMilestonesMember_f27e88d7-5f2b-4401-a70a-8c902b4e9365" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_BioDEarnoutPaymentsandMedihoneyEarnoutPaymentsMember_b9f8a933-5db8-4804-902e-ed5aabf07d57" xlink:href="iart-20250930.xsd#iart_BioDEarnoutPaymentsandMedihoneyEarnoutPaymentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContingentConsiderationTypeDomain_263a72a2-8f95-4faf-b4c6-b44f9cc8217f" xlink:to="loc_iart_BioDEarnoutPaymentsandMedihoneyEarnoutPaymentsMember_b9f8a933-5db8-4804-902e-ed5aabf07d57" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_RevenueBasedPerformanceMilestonesMember_45de3d96-6be2-4ee3-81fd-8d1f57dd4861" xlink:href="iart-20250930.xsd#iart_RevenueBasedPerformanceMilestonesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContingentConsiderationTypeDomain_263a72a2-8f95-4faf-b4c6-b44f9cc8217f" xlink:to="loc_iart_RevenueBasedPerformanceMilestonesMember_45de3d96-6be2-4ee3-81fd-8d1f57dd4861" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_RevenueBasedPerformanceMilestonesIn2023Member_ae0d7192-4acb-42d9-8f42-39220d88ebf2" xlink:href="iart-20250930.xsd#iart_RevenueBasedPerformanceMilestonesIn2023Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContingentConsiderationTypeDomain_263a72a2-8f95-4faf-b4c6-b44f9cc8217f" xlink:to="loc_iart_RevenueBasedPerformanceMilestonesIn2023Member_ae0d7192-4acb-42d9-8f42-39220d88ebf2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_FDAApprovalOfPremarketApprovalMember_71e24695-530c-443a-beb7-5a276148ab1b" xlink:href="iart-20250930.xsd#iart_FDAApprovalOfPremarketApprovalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContingentConsiderationTypeDomain_263a72a2-8f95-4faf-b4c6-b44f9cc8217f" xlink:to="loc_iart_FDAApprovalOfPremarketApprovalMember_71e24695-530c-443a-beb7-5a276148ab1b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_a581717f-f08f-45e4-a622-4ff09b35d2da" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationContingentConsiderationLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_23e855ba-3362-41b9-8802-a7781ba40b89" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_a581717f-f08f-45e4-a622-4ff09b35d2da" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedContingentLiability_64428d9a-2707-4182-aef4-0a51705fb621" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedContingentLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_23e855ba-3362-41b9-8802-a7781ba40b89" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedContingentLiability_64428d9a-2707-4182-aef4-0a51705fb621" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentForContingentConsiderationLiabilityFinancingActivities_3b44be86-5504-4437-a355-84713a0c2152" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentForContingentConsiderationLiabilityFinancingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_23e855ba-3362-41b9-8802-a7781ba40b89" xlink:to="loc_us-gaap_PaymentForContingentConsiderationLiabilityFinancingActivities_3b44be86-5504-4437-a355-84713a0c2152" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_BusinessCombinationContingentConsiderationNumberOfLiabilities_09c44899-f765-441f-bdd2-bd690286b79e" xlink:href="iart-20250930.xsd#iart_BusinessCombinationContingentConsiderationNumberOfLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_23e855ba-3362-41b9-8802-a7781ba40b89" xlink:to="loc_iart_BusinessCombinationContingentConsiderationNumberOfLiabilities_09c44899-f765-441f-bdd2-bd690286b79e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh_1f43ecc9-08d2-4346-9242-5220df88e071" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_23e855ba-3362-41b9-8802-a7781ba40b89" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh_1f43ecc9-08d2-4346-9242-5220df88e071" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_BusinessAcquisitionNumberOfContingentLiabilities_59de394d-02c5-4dc9-aa9a-1429f07b48ac" xlink:href="iart-20250930.xsd#iart_BusinessAcquisitionNumberOfContingentLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_23e855ba-3362-41b9-8802-a7781ba40b89" xlink:to="loc_iart_BusinessAcquisitionNumberOfContingentLiabilities_59de394d-02c5-4dc9-aa9a-1429f07b48ac" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://integralife.com/role/FAIRVALUEMEASUREMENTSScheduleAssetsandLiabilitiesonaRecurringBasisDetails" xlink:type="simple" xlink:href="iart-20250930.xsd#FAIRVALUEMEASUREMENTSScheduleAssetsandLiabilitiesonaRecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://integralife.com/role/FAIRVALUEMEASUREMENTSScheduleAssetsandLiabilitiesonaRecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_8dbacc3a-8723-44a4-9b8e-291640c23484" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_eb9cf092-6724-49a1-8298-4edf93cb16a4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_8dbacc3a-8723-44a4-9b8e-291640c23484" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_eb9cf092-6724-49a1-8298-4edf93cb16a4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_062fee07-e6a9-4b0d-a7a9-c15fd1ad210f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_eb9cf092-6724-49a1-8298-4edf93cb16a4" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_062fee07-e6a9-4b0d-a7a9-c15fd1ad210f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_062fee07-e6a9-4b0d-a7a9-c15fd1ad210f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_062fee07-e6a9-4b0d-a7a9-c15fd1ad210f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_062fee07-e6a9-4b0d-a7a9-c15fd1ad210f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6311bec5-f7be-459f-8982-3666f1157e6e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_062fee07-e6a9-4b0d-a7a9-c15fd1ad210f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6311bec5-f7be-459f-8982-3666f1157e6e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_094e03d0-15a1-4c6f-b4c3-16b891489d3d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6311bec5-f7be-459f-8982-3666f1157e6e" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_094e03d0-15a1-4c6f-b4c3-16b891489d3d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_e1b5eb26-ff7e-4f22-8615-a27f1b7a419c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6311bec5-f7be-459f-8982-3666f1157e6e" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_e1b5eb26-ff7e-4f22-8615-a27f1b7a419c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_ca7feb14-419d-45ff-a725-76641edafbe7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6311bec5-f7be-459f-8982-3666f1157e6e" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_ca7feb14-419d-45ff-a725-76641edafbe7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_8bc70517-d8e0-41f9-bda1-d8f9ac726f39" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_eb9cf092-6724-49a1-8298-4edf93cb16a4" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_8bc70517-d8e0-41f9-bda1-d8f9ac726f39" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_8bc70517-d8e0-41f9-bda1-d8f9ac726f39_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_8bc70517-d8e0-41f9-bda1-d8f9ac726f39" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_8bc70517-d8e0-41f9-bda1-d8f9ac726f39_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_6394556b-5a1d-4cd3-9b9a-a8304d64b2c9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_8bc70517-d8e0-41f9-bda1-d8f9ac726f39" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_6394556b-5a1d-4cd3-9b9a-a8304d64b2c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_286fa526-0dd5-41bf-9959-3e857dd14bb2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_6394556b-5a1d-4cd3-9b9a-a8304d64b2c9" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_286fa526-0dd5-41bf-9959-3e857dd14bb2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_95062fe2-6c3b-4b16-b84f-59395552f3ac" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_eb9cf092-6724-49a1-8298-4edf93cb16a4" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_95062fe2-6c3b-4b16-b84f-59395552f3ac" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_95062fe2-6c3b-4b16-b84f-59395552f3ac_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_95062fe2-6c3b-4b16-b84f-59395552f3ac" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_95062fe2-6c3b-4b16-b84f-59395552f3ac_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_ea075b57-dc16-4c37-9ddf-0fd38a6f99e1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_95062fe2-6c3b-4b16-b84f-59395552f3ac" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_ea075b57-dc16-4c37-9ddf-0fd38a6f99e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_96bb49cc-0d71-4053-8572-1ed0f95e7940" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_ea075b57-dc16-4c37-9ddf-0fd38a6f99e1" xlink:to="loc_us-gaap_InterestRateSwapMember_96bb49cc-0d71-4053-8572-1ed0f95e7940" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeForwardMember_3a6959a2-df4b-4c62-b29c-87f5f8039cbb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignExchangeForwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_ea075b57-dc16-4c37-9ddf-0fd38a6f99e1" xlink:to="loc_us-gaap_ForeignExchangeForwardMember_3a6959a2-df4b-4c62-b29c-87f5f8039cbb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CrossCurrencyInterestRateContractMember_caac0660-0fff-4935-8609-4632bd0b9ff4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CrossCurrencyInterestRateContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_ea075b57-dc16-4c37-9ddf-0fd38a6f99e1" xlink:to="loc_us-gaap_CrossCurrencyInterestRateContractMember_caac0660-0fff-4935-8609-4632bd0b9ff4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetInvestmentHedgingMember_7faf9046-47f5-416d-ac73-3aec4ad5f855" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetInvestmentHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_ea075b57-dc16-4c37-9ddf-0fd38a6f99e1" xlink:to="loc_us-gaap_NetInvestmentHedgingMember_7faf9046-47f5-416d-ac73-3aec4ad5f855" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_2a93ab43-ed75-4f8a-a081-e03e3b6c3240" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_eb9cf092-6724-49a1-8298-4edf93cb16a4" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_2a93ab43-ed75-4f8a-a081-e03e3b6c3240" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_2a93ab43-ed75-4f8a-a081-e03e3b6c3240_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_2a93ab43-ed75-4f8a-a081-e03e3b6c3240" xlink:to="loc_us-gaap_HedgingRelationshipDomain_2a93ab43-ed75-4f8a-a081-e03e3b6c3240_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_01d78f0f-43f0-4076-aa5c-674db9f8d1e4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_2a93ab43-ed75-4f8a-a081-e03e3b6c3240" xlink:to="loc_us-gaap_HedgingRelationshipDomain_01d78f0f-43f0-4076-aa5c-674db9f8d1e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_d1c22ccd-a48f-4cd6-8089-d32f56f33822" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashFlowHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_01d78f0f-43f0-4076-aa5c-674db9f8d1e4" xlink:to="loc_us-gaap_CashFlowHedgingMember_d1c22ccd-a48f-4cd6-8089-d32f56f33822" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetInvestmentHedgingMember_da93a7ed-2abe-4d04-8688-cab959dc7889" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetInvestmentHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_01d78f0f-43f0-4076-aa5c-674db9f8d1e4" xlink:to="loc_us-gaap_NetInvestmentHedgingMember_da93a7ed-2abe-4d04-8688-cab959dc7889" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_b9fe32ee-c01c-4416-8657-ba619691b3a7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_eb9cf092-6724-49a1-8298-4edf93cb16a4" xlink:to="loc_us-gaap_HedgingDesignationAxis_b9fe32ee-c01c-4416-8657-ba619691b3a7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_b9fe32ee-c01c-4416-8657-ba619691b3a7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_b9fe32ee-c01c-4416-8657-ba619691b3a7" xlink:to="loc_us-gaap_HedgingDesignationDomain_b9fe32ee-c01c-4416-8657-ba619691b3a7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_eb6d6dbd-ed9d-4f62-8998-dae8e7c85aeb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_b9fe32ee-c01c-4416-8657-ba619691b3a7" xlink:to="loc_us-gaap_HedgingDesignationDomain_eb6d6dbd-ed9d-4f62-8998-dae8e7c85aeb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NondesignatedMember_169655fd-b73e-4e18-8170-d977afe69eb7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NondesignatedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_eb6d6dbd-ed9d-4f62-8998-dae8e7c85aeb" xlink:to="loc_us-gaap_NondesignatedMember_169655fd-b73e-4e18-8170-d977afe69eb7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosureAbstract_e0ff1ef8-38cd-44f9-ab9e-1c5b756b5661" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_8dbacc3a-8723-44a4-9b8e-291640c23484" xlink:to="loc_us-gaap_AssetsFairValueDisclosureAbstract_e0ff1ef8-38cd-44f9-ab9e-1c5b756b5661" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_8a741fe0-6345-4251-b8a7-24dbd27d65c9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_e0ff1ef8-38cd-44f9-ab9e-1c5b756b5661" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_8a741fe0-6345-4251-b8a7-24dbd27d65c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_iart_ShortTermInvestmentsFairValueDisclosure_5ce6ab02-f294-419e-9f04-e5eb95e10d1a" xlink:href="iart-20250930.xsd#iart_ShortTermInvestmentsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_e0ff1ef8-38cd-44f9-ab9e-1c5b756b5661" xlink:to="loc_iart_ShortTermInvestmentsFairValueDisclosure_5ce6ab02-f294-419e-9f04-e5eb95e10d1a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_85eaa632-d72c-46e9-8b90-d25ac0dbc64e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_e0ff1ef8-38cd-44f9-ab9e-1c5b756b5661" xlink:to="loc_us-gaap_DerivativeAssets_85eaa632-d72c-46e9-8b90-d25ac0dbc64e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_28ef1238-d683-4042-a588-5f303408a3a7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_e0ff1ef8-38cd-44f9-ab9e-1c5b756b5661" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_28ef1238-d683-4042-a588-5f303408a3a7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_5dd8d09f-035a-475b-9237-005c87fab312" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_8dbacc3a-8723-44a4-9b8e-291640c23484" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_5dd8d09f-035a-475b-9237-005c87fab312" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilities_ccf6907c-dd2c-407f-911b-28942f527035" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_5dd8d09f-035a-475b-9237-005c87fab312" xlink:to="loc_us-gaap_DerivativeLiabilities_ccf6907c-dd2c-407f-911b-28942f527035" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_1d27441e-d401-42d3-b512-12adbbe6610f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BusinessCombinationContingentConsiderationLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_5dd8d09f-035a-475b-9237-005c87fab312" xlink:to="loc_us-gaap_BusinessCombinationContingentConsiderationLiability_1d27441e-d401-42d3-b512-12adbbe6610f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_9af48dfe-0196-4076-8344-cb5e990765d9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_5dd8d09f-035a-475b-9237-005c87fab312" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_9af48dfe-0196-4076-8344-cb5e990765d9" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-roles-2025.xsd#eedm"/>
  <link:definitionLink xlink:role="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseExcludingAcquiredInProcessCost" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ResearchAndDevelopmentExpenseExcludingAcquiredInProcessCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementAbstract" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseExcludingAcquiredInProcessCost" xlink:type="arc" order="691"/>
  </link:definitionLink>
</link:linkbase>
