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.

A court is any person or institution, often as a government institution, with the authority to adjudicate legal disputes between parties and carry out the administration of justice in civil, criminal, and administrative matters in accordance with the rule of law. In both common law and civil law legal systems, courts are the central means for dispute resolution, and it is generally understood that all people have an ability to bring their claims before a court. Similarly, the rights of those accused of a crime include the right to present a defense before a court.