Literally, the phrase means a bomb-maker was blown off the ground (hoist) by his own bomb (petard). It commonly refers to an ironic reversal in which one is taken down by one's own scheme.

Aside from historical references to siege warfare, and occasional contemporary references to fireworks, petard is almost always encountered in variations of the phrase " hoist with one's own petard," …

Jul 17, 2020 · The OED offers several different senses of this word in its entry for ‘petard’, but the earliest and chief meaning is: ‘A small bomb made of a metal or wooden box filled with powder, used …

This term has its origin in medieval times when a military commander would send forward one of his engineers with a cast-iron container full of gunpowder, called a petard, to blow up a castle gate, …

Hoist is the past participle of hoise, an earlier form of the verb hoist, "to be lifted up," while a petar or petard is a small bomb used in early modern warfare. The phrase "hoist with his own petard" …

3 meanings: 1. (formerly) a device containing explosives used to breach a wall, doors, etc 2. → See hoist with one's own petard.... Click for more definitions.

A petard was a very small bomb typically used for blowing holes in doors and gates, and not for bombing an entire troop or village. They had cannons for those bigger jobs.

There are four meanings listed in OED's entry for the noun petard, one of which is labelled obsolete. See ‘Meaning & use’ for definitions, usage, and quotation evidence.

petard: A small bell-shaped bomb used to breach a gate or wall.

Petard definition: A metal cone or box filled with explosives, fastened in warfare to walls and gates and exploded to force an opening.