The Collaborative International Dictionary
Res \Res\ (r?z), n.; pl. Res. [L.] A thing; the particular thing; a matter; a point.
Res gest[ae] [L., things done] (Law), the facts which form
the environment of a litigated issue.
Res judicata [L.] (Law), a thing adjudicated; a matter no longer open to controversy.
Douglas Harper's Etymology Dictionary
Latin, "a point decided by competent authority."
n. (context legal English) An issue that is before a court, has already been decided by another court, and therefore must be dismissed by the current court.
n. a matter already settled in court; cannot be raised again [syn: res adjudicata]
Res judicata or res iudicata, also known as claim preclusion, is the Latin term for "a matter [already] judged", and refers to either of two concepts: in both civil law and common law legal systems, a case in which there has been a final judgment and is no longer subject to appeal; and the legal doctrine meant to bar (or preclude) continued litigation of a case on same issues between the same parties. In this latter usage, the term is synonymous with " preclusion".
In the case of res judicata, the matter cannot be raised again, either in the same court or in a different court. A court will use res judicata to deny reconsideration of a matter.
The legal concept of res judicata arose as a method of preventing injustice to the parties of a case supposedly finished, but perhaps mostly to avoid unnecessary waste of resources in the court system. Res judicata does not merely prevent future judgments from contradicting earlier ones, but also prevents litigants from multiplying judgments, and confusion.