amicus curiae

An amicus curiae (also spelled amicus curiæ; plural amici curiae) is someone, not a party to a case, who volunteers to offer information to assist a court in deciding a matter before it. The information provided may be a legal opinion in the form of a brief (which is called an amicus brief when offered by an amicus curiae), a testimony that has not been solicited by any of the parties, or a learned treatise on a matter that bears on the case. The decision on whether to admit the information lies at the discretion of the court. The phrase amicus curiae is legal Latin and literally means "friend of the court".