A supreme court (also called a court of last resort, instance, or judgment; a high or highest court; apex court in South Asia) is in some jurisdictions the highest judicial body within that jurisdiction's court system, whose rulings are not subject to further review by another court. The designations for such courts differ among jurisdictions. Courts of last resort typically function primarily as appellate courts, hearing appeals from the lower trial courts or intermediate-level appellate courts. Many countries in fact have multiple "supreme courts," with each being the court of last resort for a particular geographical region or on a particular area of law. The United States, having a federal system of government, has a single Supreme Court of the United States, but each U.S. state furthermore has its own high court over which the U.S. Supreme Court only has jurisdiction on issues of federal law.