Original jurisdiction is the authority of a court to try a case, as distinguished from appellate jurisdiction to hear appeals from trial judgments. Original jurisdiction is the court's authority to hear the claim in the first instance, rather than on appeal. The court rules on issues directly, rather than on matters which are referred to it after being heard by another court.
Under the U.S. Constitution, the Supreme Court has "original jurisdiction" over several small but important categories of cases. That means that the parties can bring such disputes directly to the Supreme Court.
The Supreme Court has original but not exclusive jurisdiction of: