The opening at the end of the gut where solid waste leaves the body. Doctors and biology books use this Latin word; it is the polite scientific name, not a joke and not an insult in medical English. In everyday talk people often avoid it, or use a childish or rude word instead. You need it for health class and the doctor’s office. Formal anatomy; if someone uses it to laugh at a body, that is their manners, not the word’s job.

肛門（醫療、課堂用語；口語另有粗話，上課不要用）