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.

---

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

---

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

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

As third party delivery services such as DoorDash grew in popularity, Pizza Hut fell behind without the advantage of delivery convenience, said Aneurin Canham-Clyne, a reporter for trade publication Restaurant Drive.

From Los Angeles Times ● Jun. 16, 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