1. A small bell-shaped bomb used to breach a gate or wall.
2. A loud firecracker.

[French pétard, from Old French, from peter, to break wind, from pet, a breaking of wind, from Latin pēditum, from neuter past participle of pēdere, to break wind.]

WORD HISTORY   The French used pétard, "a loud discharge of intestinal gas," for a kind of infernal engine for blasting through the gates of a city. "To be hoist by one's own petard," a now proverbial phrase apparently originating with Shakespeare's Hamlet (around 1604) not long after the word entered English (around 1598), means "to blow oneself up with one's own bomb, be undone by one's own devices." The French noun pet, "fart," developed regularly from the Latin noun pēditum, from the Indo-European root *pezd-, "fart."

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.