What does amicus mean?
Amicus is a Latin noun meaning 'friend', borrowed into English chiefly through legal terminology rather than everyday speech. Its dominant modern use is in the phrase 'amicus curiae' — literally 'friend of the court' — which denotes someone who is not a party to a case but offers expertise, information, or argument to help the court reach its decision, typically by filing what is known as an amicus brief. This practice is especially visible in appellate courts such as the US Supreme Court, where interested organisations routinely submit such briefs. Beyond the courtroom, 'amicus' retains its classical sense of a trusted friend, reflecting Roman ideals of loyalty and reciprocal obligation. Because it survives almost entirely within fixed legal phrases, the word carries a formal, scholarly register; using it elsewhere can seem affected. It shares its root with familiar English words such as 'amiable', 'amity', and even 'enemy' (via Latin 'inimicus').
nounA Latin word meaning 'friend', used in English chiefly in the legal phrase 'amicus curiae' — a 'friend of the court' who is not a party to a case but offers information or argument to assist the court.
- A friend (the original Latin sense, rarely used directly in modern English).
- A person who is not a party to litigation but provides information or argument to assist a court, as in 'amicus curiae'.
"The retired judge appeared as an amicus curiae, submitting a brief to clarify the constitutional question."
"She filed an amicus brief on behalf of several civil liberties organisations."
"To the Romans, an amicus was more than an acquaintance — it was a bond of loyalty and mutual obligation."
The Latin plural 'amici' is standard in legal contexts, often referring to multiple parties submitting joint amicus briefs.
"Several former attorneys general signed on as amici curiae in the case."
In court, an 'amicus curiae' is literally a 'friend of the court' — someone with no stake in the case who shows up just to help the judges think it through.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of amicus
Amicus comes directly from Latin, where it was the ordinary word for 'friend' and carried strong connotations of loyalty and mutual obligation in Roman social life. English adopted it largely intact through legal Latin, preserving it in the phrase 'amicus curiae', attested in English legal usage from at least the early 17th century. The same Latin root 'am-' (to love) underlies English cognates such as 'amiable', 'amity', and 'amateur', while its negative counterpart 'inimicus' gave rise to 'enemy'.
How amicus is actually used
Almost entirely confined to formal legal contexts in modern English; outside phrases like 'amicus curiae' and 'amicus brief', the bare Latin noun is rare and would be considered scholarly or pedantic.
Easily confused with amicus
'Amicable' is an English adjective describing friendliness or goodwill between people, while 'amicus' is a Latin noun used almost exclusively in the fixed legal phrase 'amicus curiae'.