[n] excretory opening at the end of the alimentary canal
arse, arsehole, asshole
abdomen, appendix, asshole, blind gut, bowels, brain, bung, bunghole, cecum, colon, duodenum, endocardium, entrails, foregut, giblets, gizzard, guts, heart, hindgut, innards, inner mechanism, insides, internals, intestine, inwards, jejunum, kidney, kishke