The term is also used in property litigation, where a person may be appointed to act on behalf of an estate in court proceedings, when the estate's proper representatives are unable or unwilling to act.
The term is also sometimes used to refer to a judge who only participates in a particular case or a limited set of cases, and does not have the same status as the other judges of the court. This is more commonly called a judge ad hoc. It is particularly common in international courts, and is rarer elsewhere.
The Latin term translates literally as "for the lawsuit" or "for the proceeding".