third party

American  

noun

1. any party to an incident, case, quarrel, etc., who is incidentally involved.

2. (in a two-party system) a political party formed as a dissenting or independent group from members of one or both of the two prevailing major parties.

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third party British  

noun

1. a person who is involved by chance or only incidentally in a legal proceeding, agreement, or other transaction, esp one against whom a defendant claims indemnity

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adjective

1. insurance providing protection against liability caused by accidental injury or death of other persons or damage to their property

   third-party insurance

Etymology

Origin of third party

An Americanism dating back to 1795–1805

Example Sentences

North Carolina, where the Ammels lived, is one of just a handful of states with a “homewrecker law” that allows a jilted spouse to sue a third party for damages for a marital breakup.

From The Wall Street Journal • Apr. 18, 2026

The lawsuits attempted to skirt around Section 230 by suing on the basis of the platform’s internal features, not third party content posted on the platforms.

From Salon • Apr. 16, 2026

We don’t actually know 100% what she/he said or did — only that she reacted strongly and that response was reported to a third party.

From MarketWatch • Apr. 13, 2026

The third party is the Angels, who acknowledged during the Skaggs family’s wrongful death civil trial that they had been paying for Kay’s legal fees for months.

From Los Angeles Times • Apr. 7, 2026

A man that thinks anything he dont understand all about must be crooked and that first chance he gets he’s morally bound to tell the third party what’s none of his business to tell.

From "The Sound and the Fury" by William Faulkner

Related Words

• mediator