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

The benefits of third-party testing are wide-ranging. —Brynn Cooksey, Forbes.com, 7 Sep. 2025

In an August memo to the Board of Supervisors, Martinez proposed hiring a third-party administrator to oversee jail health care instead. —Kelly Davis, San Diego Union-Tribune, 7 Sep. 2025

Noun

Affordable Care Act policies cannot be traded by third parties and the federal government doesn’t sell or repurchase Affordable Care Act insurance coverage. —Steve Weisman, Forbes.com, 11 Sep. 2025

During one game, Robinson, Vasquez and a third party bet a combined $2,200 on Robinson to underperform, and a $15,950 payout was redistributed among those who had bet, the NCAA said. —Jackson Thompson, FOXNews.com, 11 Sep. 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