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

“We have been fielding incoming investor debates around fears from third party credit card data into results and which should amplify today’s strong results,” Siegel wrote.

From Barron's • Jun. 2, 2026

Insurers report as “affiliated” debt or equity of an affiliate as well as investments sold by an affiliate but backed by a third party.

From The Wall Street Journal • May 26, 2026

New government rules now mean only a learner driver can book their own test, part of a crackdown on third party operators using bots to hoover up thousands of slots.

From BBC • May 16, 2026

In Rockefeller’s defense, as a business owner, you would rather have a job done by your own trusted people than pay an unknown third party to handle the task.

From Barron's • May 2, 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