third party

American  

noun

third parties plural

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

Other Word Forms

Noun Inflected Forms

• third parties
  plural

Etymology

Origin of third party

An Americanism dating back to 1795–1805

Example Sentences

See Examples For:

third party

Domani plays a prominent role in New York City’s construction industry, acting as an independent third party to inspect work sites to ensure construction complies with safety codes.

From The Wall Street Journal ● Jul. 27, 2026

“A third party vendor was hired to facilitate the pyrotechnics,” said Stephanie Rudnick, head of communications for the Angel City Football Club, from her home in Australia.

From Los Angeles Times ● Jul. 5, 2026

With joint tenancy with the rights of survivorship, you own 100% of your home together, and he could not sell to a third party.

From MarketWatch ● Jun. 24, 2026

Anthropic described the loophole discovered by this third party -- identified by several media outlets as Amazon -- as "narrow" and said the software vulnerabilities it exposed were "minor."

From Barron's ● Jun. 14, 2026

Any third party whom you might make their commander cannot immediately seize enough authority to harm you.

From "The Prince" by Niccolò Machiavelli

Related Words

• mediator