An appellate court, commonly called a court of appeal(s), appeal court, court of second instance or second instance court, is any court of law that is empowered to hear an appeal of a trial court or other lower tribunal. In much of the world, court systems are divided into at least three levels: the trial court, which initially hears cases and reviews evidence and testimony to determine the facts of the case; at least one intermediate appellate court; and a supreme court (or court of last resort) which primarily reviews the decisions of the intermediate courts, often on a discretionary basis. A particular court system's supreme court is its highest appellate court. Appellate courts nationwide can operate under varying rules.