Definition of "fossa"

(anatomy) A pit, groove, cavity, or depression.  examples

(astronomy) A long, narrow, shallow depression on the body of an extraterrestrial body, such as a planet or moon.  examples

A large nocturnal reddish-brown catlike mammal (Cryptoprocta ferox) of the civet family, endemic to the rainforests of Madagascar. It is slender, long-tailed and has retractile claws and anal scent glands.  examples