in some systems of classification, any of an order (Cetacea) of nearly hairless, fishlike water mammals, lacking external hind limbs, but having paddlelike forelimbs, including whales, porpoises, and dolphins
Any of various aquatic, chiefly marine mammals of the order Cetacea, including the whales, dolphins, and porpoises, characterized by a nearly hairless body, anterior limbs modified into broad flippers, vestigial posterior limbs, and a flat notched tail.
adjective also ce·ta·ceous(sĭ-tāˈshəs)
Of, relating to, or belonging to the order Cetacea.