What type of jurisdiction primarily composes the Supreme Court's workload?

The Supreme Court primarily operates under appellate jurisdiction, which means it primarily hears cases on appeal from lower courts. This is a significant aspect of the Court's role in the American judicial system, as it serves to review decisions made by federal and state courts. Most cases come to the Supreme Court after being decided by lower courts, where one party seeks a review of the decision.

The Court's ability to review these appeals allows it to interpret the Constitution, address significant legal questions, and ensure uniformity in the application of federal law across the country. Although the Supreme Court has the power to exercise original jurisdiction in a limited number of cases—such as those involving ambassadors or disputes between states—these cases are rare and do not make up the majority of the Court’s caseload. Other forms of jurisdiction, like concurrent jurisdiction, refer to situations where multiple courts can hear the same case, but again, this is not the primary nature of the Supreme Court's work. Federal jurisdiction encompasses cases involving federal law, but this is a broader category that includes both original and appellate jurisdiction in various federal courts, not just the Supreme Court.