petard

thumb|upright=1.2|right|A petard, from a seventeenth-century manuscript of military designs thumb|upright|right|A 19th-century British army petard (in center, projecting from the copper circle), mounted on a madrier, with braces

A petard is a small bomb used for blowing up gates and walls when breaching fortifications, originally invented in France in 1579. A typical petard was a conical or rectangular metal device containing of gunpowder, with a slow match for a fuse.