amicus

noun

ami·​cus ə-ˈmē-kəs  -ˈmī- 

plural amici ə-ˈmē-ˌkē 

-ˈmī-ˌsī

: someone (such as a professional person) or something (such as an organization) that is not a party to a particular case but that is allowed by the court upon petition or by the court's request to advise it in respect to some matter of law that directly affects the case in question : amicus curiae

I'd like to urge you to begin thinking about filing a brief as amicus in this case.

—Jonathan Mahler

… Mr. Benkard recently had joined in an … amicus brief seeking overturn of a U.S. Claims Court judgement …

—The National Law Journal

Two dozen prominent law professors and economists called attention to this problem in an amicus brief submitted to the FTC's administrative tribunal.

—Rachel Chiu

Examples of amicus in a Sentence

Recent Examples on the Web

The ranchers decided to write an amicus brief after seeing that eight counties were setting aside money to write a brief in support of the oil companies. — Ian James, Los Angeles Times, 5 Sep. 2026

America First Legal also filed an amicus brief arguing the sanctions should be undone. — Austin Horn, Miami Herald, 24 Aug. 2026

Nearly two dozen states — all of which are led by Democrats — filed an amicus brief in support of that lawsuit. — Kat Lonsdorf, NPR, 11 Aug. 2026

The coalition filed an amicus brief urging a federal judge in Idaho to block enforcement of the law while the lawsuit moves forward, arguing that the measure is unconstitutional and undermines the rights and safety of transgender students. — Darrielle Fair, CBS News, 7 Aug. 2026

Word History

First Known Use

1916, in the meaning defined above

Phrases Containing amicus

• amicus curiae

Legal Definition

amicus

noun

ami·​cus ə-ˈmē-kəs, -ˈmī- 

plural amici -ˈmē-ˌkē, -ˈmī-ˌsī 

: amicus curiae