/pi tahrd"/ , n.
1. an explosive device formerly used in warfare to blow in a door or gate, form a breach in a wall, etc.
2. a kind of firecracker.
3. ( cap. ) Also called Flying Dustbin . a British spigot mortar of World War II that fired a 40-pound (18 kg) finned bomb, designed to destroy pillboxes and other concrete obstacles.
4. hoist by or with one's own petard , hurt, ruined, or destroyed by the very device or plot one had intended for another.
[ 1590-1600; pet ( er ) to break wind (deriv. of pet peditum a breaking wind, orig. neut. of ptp. of pedere to break wind) + -ard -ARD ]