third party

American  

noun

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.

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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

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adjective

1. insurance providing protection against liability caused by accidental injury or death of other persons or damage to their property

   third-party insurance

Etymology

Origin of third party

An Americanism dating back to 1795–1805

Example Sentences

Are you tenants in common, where one party can leave their share to a third party?

From MarketWatch • Apr. 16, 2026

They said that Meta’s design and delivery of third party content is in and of itself problematic, causing social media addiction and putting children at risk for exploitation.

From Salon • Apr. 16, 2026

“A third party that agreed to pay his legal fees and costs has refused to pay, leaving Kay’s current counsel with more than $130,000 in unpaid fees and out-of-pocket expenses,” Gerger wrote.

From Los Angeles Times • Apr. 7, 2026

If using a computational tool to process information constitutes “disclosure” to a third party, the implications extend to everyone who has ever stored a confidential document in the cloud or sent an email.

From The Wall Street Journal • Apr. 6, 2026

"Yes, sir, he put through the sale—though he made it clear that he was buying Soldier Island for a third party, unnamed."

From "And Then There Were None" by Agatha Christie

Related Words

• mediator