third-party claim n1 : a claim made against a third party in a third-party complaint compare counterclaim , cross-action , cross-claim
2 : a claim made by an injured third party (as a third-party beneficiary of workers' compensation insurance) against an insurer or insured for indemnification
Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.