petard UK /pɪˈtɑːd/US /pɪˈtɑɹd/noun 3verb 1forms 3phrases 1 noun3 •Anything potentially explosive, in a non-literal sense. •(historical) A small, hat-shaped explosive device, used to breach a door or wall.For tis the sport to haue the enginer / Hoist with his ovvne petar, an't shall goe hard / But I vvill delue one yard belovve their mines, / And blovve them at the Moone: […] — 1599 •(rare) A loud firecracker. verb1 •(no longer used) To attack or blow a hole in (something) with a petard. formspetarded · petarding · petards Phrases with petard hoist by one's own petardHurt or destroyed by one's own plot or device intended for another; "blown up by one's own bomb".