trebuchet UK /ˈtɹɛbəʃɛt/US /ˈtɹɛb.juˌʃɛt/noun 2verb 1forms 3 noun2 •A medieval siege engine consisting of a large pivoting arm heavily weighted on one end.Medieval trebuchets are said to have been capable of launching 90-kg projectiles over distances of more than 300 meters. •A torture device for dunking suspected witches by means of a chair attached to the end of a long pole. verb1 •To shoot with a trebuchet. formstrebucheted · trebucheting · trebuchets