Which statement correctly defines res judicata?

• A. A judge's authority to retry a case on appeal
• B. A rule allowing relitigation after a final judgment
• C. A requirement to file new evidence on appeal
• D. The principle that a matter cannot be relitigated once finally adjudicated

Answer: (D)

Res judicata means that after a court has issued a final judgment on the merits, the same claim cannot be relitigated by the same parties in a future action. This principle ensures finality and prevents endless litigation. The statement that a matter cannot be relitigated once finally adjudicated captures this idea precisely, which is why it’s the best definition. The other options describe procedures unrelated to the bar on bringing the same claim again: appellate retry authority, relitigating after a final judgment, and requirements to file new evidence on appeal.