The New Student's Reference Work/Petard

Petard (pē-tärd′), an instrument for blowing open the gates of a fortress or demolishing palisades. It consisted of an iron or wooden case filled with powder and ball; this was firmly fastened to a plank provided with hooks, by which it was securely attached to a gate. The petard, which was lighted by a slow match, has been superseded by powder-bags.