1. A judicial decision that first definitively settled an important legal rule or principle and that has since been often and consistently followed. • An example is Miranda v. Arizona, 384 U.S. 436, 86 S.Ct. 1602 (1966) (creating the exclusionary rule for evidence improperly obtained from a suspect being interrogated while in police custody). Cf. LANDMARK DECISION.
2. An important, often the most important, judicial precedent on a particular legal issue.
3. Loosely, a reported case that is cited as the dispositive authority on an issue being litigated. — Also termed (in sense 3) ruling case.
