noun \si-ˈtā-shən\

: a mammal (such as a whale, dolphin, or porpoise) that lives in the ocean

Full Definition of CETACEAN

:  any of an order (Cetacea) of aquatic mostly marine mammals that includes the whales, dolphins, porpoises, and related forms and that have a torpedo-shaped nearly hairless body, paddle-shaped forelimbs but no hind limbs, one or two nares opening externally at the top of the head, and a horizontally flattened tail used for locomotion
cetacean adjective
ce·ta·ceous \-shəs\ adjective

Origin of CETACEAN

ultimately from Latin cetus whale, from Greek kētos
First Known Use: 1835


noun    (Concise Encyclopedia)

Any of the exclusively aquatic placental mammals constituting the order Cetacea. They are found in oceans worldwide and in some freshwater environments. Modern cetaceans are grouped in two suborders: about 70 species of toothed whales (Odontoceti) and 13 species of toothless baleen whales (Mysticeti). They have a tapered body, no external hind limbs, and a tail ending in a horizontal blade of two lobes, or flukes. Cetaceans must come to the water's surface to breathe through blowholes located on top of their head. See also whale.


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