In Ancient Greek, the word kētos (, plural kētē or kētea, κήτη or κήτεα)—Latinized as cetus—denotes a large fish, a whale, a shark, or a sea monster. The sea monsters slain by Perseus and Heracles were each referred to as a cetus by ancient sources. The term cetacean (for whale) originates from cetus. In Greek art, cetea were depicted as serpentine fish. The name of the mythological figure Ceto is derived from ketos. The name of the constellation Cetus also derives from this word.