肛门

Also known as arsehole, asshole, bung-hole, bunghole, butthole, bumhole, anal

In mammals, invertebrates and most fish, the anus (: anuses or ani; from Latin, 'ring' or 'circle') is the external body orifice at the exit end of the digestive tract (bowel), i.e. the opposite end from the mouth. Its function is to facilitate the expulsion of waste that remains after digestion.