The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest, such as bones; food material after all the nutrients have been extracted, for example cellulose or lignin; ingested matter which would be toxic if it remained in the digestive tract; and dead or excess gut bacteria and other endosymbionts.

Anusim (, ; singular male, Anús, ; singular female, Anusáh, , meaning "Coerced") is a legal category of Jews in halakha (Jewish religious law) who were forced to abandon Judaism against their will, typically while forcibly converted to another religion. The term "anusim" itself is most properly translated as the "coerced [ones]" or the "forced [ones]".