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

Such laws would require third-party audits of social media algorithms to identify any harmful patterns, such as serving eating-disorder content to young girls more than to other groups. — Allison Parshall, Scientific American, 20 Oct. 2026

Morgan founded the Alberta Independence Party in 2000 and is also the founder of Pathway to Independence, a third-party advertising group that advocates for an independent Alberta. — Sheena Rossiter, NPR, 19 Oct. 2026

Noun

Clogging a ballot with third party candidates to siphon off votes from the other major party is a long-standing tactic in the country’s two-party system. — Nicholas Riccardi, Los Angeles Times, 23 Oct. 2026

According to a lawsuit, a coding error resulted in erroneous scores being generated and reported to third parties over a three-week period between March and April 2022. — Brian Sloan,dan Avery, CNBC, 23 Oct. 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