Appealing; relating to appeals; appellate.n. In law: One who appeals or removes a cause from a lower to a higher tribunal.n. One who prosecutes another for a crime, such as felony or treason.n. One who looks to any tribunal for corroboration or vindication.n. One who challenges or summons another to single combat.n. Eccles., one of the French clergy who, in the Jansenist controversy, rejected the bull Unigenitus, issued in 1713 by Pope Clement XI. against Quesnel's “Réflexions morales sur le Nouveau Testament,” and appealed to the pope “better informed,” or to a general council.n. One who appeals or presents a request.