trebuchet

From Old French trebuchet, trebuket et al. (modern trébuchet), from trebuchier (“to overthrow, topple”), from tres- + buchier, from Old French buc (“trunk of the body”), from Old Frankish būk (“belly, trunk, torso”), from Proto-Germanic būkaz (“belly, abdomen, trunk”), from Proto-Indo-European bʰōw- (“to blow, swell”). Cognate with Old High German būh (“belly”), Old English būc (“belly, trunk”). More at bouk.