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

However, when there is no third-party income information—self-reporting—tax compliance is just 55%. —Kelly Phillips Erb, Forbes, 12 Mar. 2025

See More South's Best 2025 Winners South's Best Voting Process An online survey was conducted by third-party agency Proof Insights among Southern Living Consumers, asking them to rate their favorite places across the South. —Stacey Lastoe, Southern Living, 11 Mar. 2025

Noun

Editorial Note: Opinions, analyses, reviews or recommendations expressed in this article are those of the Select editorial staff’s alone, and have not been reviewed, approved or otherwise endorsed by any third party. —Jason Stauffer, CNBC, 28 Feb. 2025

Quality: Supplement brands may have their products reviewed for quality by third parties. —Brittany Lubeck, Ms, Rdn, Verywell Health, 25 Feb. 2025

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 party sense 1a, b