Meaning

noun an engine that provided medieval artillery used during sieges; a heavy war engine for hurling large stones and other missiles

noun Asiatic wild ass

originFrom Middle English onager, onagir (“wild ass; military catapult”), from Anglo-Norman onager, Middle French onager, onagre, Old French onager, onagre (“wild ass; military catapult”) (modern French onagre), from Late Latin onager (“large siege engine”), Latin onager (“wild ass”), from Hellenistic Ancient Greek ὄναγρος (ónagros, “wild ass”), Byzantine Ancient Greek ὄναγρος (ónagros, “large siege…

Etymology from Wiktionary, CC BY-SA 3.0