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

Any and all present or future interests of a Party in any trust created by a third party shall remain the Separate Property of that Party.

From The Wall Street Journal • Apr. 23, 2026

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

Goldman says this strategy is simply a workaround to hold platforms accountable for problematic third party content it publishes.

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

Somebody, a third party, agreed the fishing had gone sour, the bank seemed all dried up real sudden, he’d been thinking on fishing at Elliot Head, couldn’t tell but maybe things was better there.

From "Snow Falling on Cedars: A Novel" by David Guterson

Related Words

• mediator