petard
pe.tard \p*-'ta:r(d)\ n [MF, fr. peter to break wind, fr. pet expulsion of intestinal gas,]fr. L peditum, fr. neut. of peditus, pp. of pedere to break wind; akin to Gk bdein to break wind 1: a case containing an explosive to break down a door or gate or breach a wall 2: a firework that explodes with a loud report