backsides, behinds, booties(slang), bottoms, breeches, bums, buns, buttocks, butts, cabooses, cans, cheeks, derrieres(or derrières), duffs, fannies, fundaments, hams, haunches, heinies(slang), hunkers, nates, posteriors, rear ends, rears, rumps, seats, tail ends, tails, tushes(slang)

beams, sternsmoons(slang)