Amicus curiae is a Latin term meaning "friend of the court". The plural form is amici curiae. A person or an organization which is not a party to the case but has an interest in an issue before the court may file a brief or participate in the argument as a friend of the court. An amicus curiae asks for permission to intervene in a case usually to present their point of view in a case which has the potential of setting a legal precedent in their area of activity, often in civil rights cases. Usually the court must give permission for the brief to be filed and arguments may only be made with the agreement of the party the amicus curiae is supporting, and that argument comes out of the time allowed for that party's presentation to the court.
The term may also refer to an outsider who may inform the court on a matter a judge is doubtful or mistaken in a matter of law. An amicus curiae application by a non-relative may be made to the court in favor of an infant or incompetent person. The court may give the arguments in the amicus curiae brief as much or as little weight as it chooses.