Amicus curiae: (Latin) friend of the court.
A person, lawyer or not, asking for permission to speak to the Court in a case in which they are neither plaintiff or defendant, usually to point out a notorious fact not known to the Court (such as the sudden death of a party) or a point of law or recent change in the law or a law case on point not apparently known to the Court.
From Re Pehlke 1939 4 DLR 725, a bankruptcy case:
"The words amicus curiae mean friend of the court;
and the term is applied to one who suggests something for the
information of the court....
"The term is
generally applied to a solicitor of the court who, being
present, makes some suggestion to the court in regard to the
matter before it and it is more rarely applied to counsel
arguing the case. Also the term is used of persons who have no
right to appear in a suit but are allowed to protect their own
interest, and finally to a stranger who, being in court, calls
the court's attention to some error in the proceedings....
"The
practice ought to be confined to cases of the sort above
mentioned and in the case where counsel simply comes and
presents a point more or less roughly the practice should be
discouraged."
In
R v Lee, 1998 125 CCC 3d 363, the Northwest Territories Court said:
"There are traditionally three situations in which the court
appoints an amicus: (a) where there is a matter of public
interest in which the court invites the Attorney-General or some
other capable individual to intervene; (b) to prevent an
injustice, for example, to make submissions on points of law that
may have been overlooked; and (c) to represent the unrepresented. Generally, an amicus curiae is a barrister
who assists the court, at the court's request, and is
disinterested."
The term
amicus curiae can be distinguished from an
intervenor, the latter having an interest in the proceedings (an advocate), the former being disinterested; merely a friend of the Court.