third-party

1 of 2

adjective

third-par·​ty ˈthərd-ˈpär-tē 

1

: of, relating to, or involving a third party

third-party insurance

2

: of, relating to, or being software that is created by a vendor to be compatible with the products of another vendor

third party

2 of 2

noun

1

: a person other than the principals

a third party to a divorce proceeding

insurance against injury to third parties

2

a

: a major political party operating over a limited period of time in addition to two other major parties in a nation or state normally characterized by a two-party system

b

: minor party

Examples of third-party in a Sentence

Recent Examples on the Web

Adjective

Alaska sends the four highest finishers in its nonpartisan primary onto the general election – all but ensuring that the general includes candidates from both parties and even independents or third-party hopefuls. —Tom Charron, Mercury News, 6 Mar. 2026

Cymbiotika’s ingredients are all third-party tested and GMP-certified, too. —Brianna Peters, Vogue, 6 Mar. 2026

Noun

Assuming the toymakers’ claims are valid, Cross said, the apparent lack of oversight raises questions about companies’ ability to track how developers and third parties are using their systems. —Kevin Collier, NBC news, 3 Mar. 2026

Soon after, the foundation hired a third party to oversee its digital architecture. —Michael Adno, Rolling Stone, 3 Mar. 2026

Word History

First Known Use

Adjective

1901, in the meaning defined at sense 1

Noun

1641, in the meaning defined at sense 1

Kids Definition

third party

noun

1

: a person other than the main participants

a third party to the legal proceedings

2

a

: a political party operating usually for a limited time in addition to the two major parties in a 2-party system

b

: minor party

Legal Definition

third party

see also:

party sense 1a, b