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

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

Miami Mayor Eileen Higgins joined the mayors of Boston, Cincinnati and Kansas City, Missouri, in amicus briefs filed with the Supreme Court earlier this year opposing the termination. — Antonio María Delgado, Miami Herald, 8 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

Scholars and practitioners now advise Chinese entities on responding promptly to foreign litigation, avoiding default judgments, and presenting Chinese legal positions through expert testimony and amicus briefs. — Mark Jia, Foreign Affairs, 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