n. a person or entity who has an interest (financial or protection of some legal rights) in the subject matter of a lawsuit and, therefore, can join in the lawsuit as he/she/it wishes, or may be brought into the suit (as an unnecessary party) by one of the parties to the legal action. However, the judgment may leave some matters undecided. A proper party is distinguished from a "necessary party," which the court will order joined in (brought into) the suit if any judgment is to be reached. Example: Marianne Steel and Isaac Iron both own lots with vacation cabins up the hill from Allen Albright's ranch, and for years both Steel and Iron have driven up an old road across Albright's property to reach their cabins. Steel brings a quiet title action against Albright to establish a "prescriptive easement" over the roadway, but Iron does not. The court rules in favor of Steel, but says nothing about Iron. In this case Iron is a "proper party," but did not choose to participate, and it was not necessary for Steel to obtain a judgment for herself. See also: necessary party party

Henderik Alex (Erik) Proper (born 22 May 1967) is a Dutch computer scientist, an FNR PEARL Laureate, and a senior research manager within the Computer Science (ITIS) department of the Luxembourg Institute of Science and Technology (LIST).