A cetacean is a member of the family of large aquatic mammals such as whales, dolphins, and porpoises. They have tails rather than hind limbs, and they have flippers instead of forearms.

The word cetacean comes from the Latin word cetus, which was used to refer to any large sea creature, and the Greek word ketos, which was a sea monster or whale. The suffix acea means "of the nature of," so cetacean describes a creature belonging to the family of whales or dolphins. As an adjective, the word is used to describe things related to this group. If you like whales and dolphins, you may enjoy cetacean stories like "Moby Dick."

Definitions of cetacean
  1. noun
    large aquatic carnivorous mammal with fin-like forelimbs no hind limbs, including: whales; dolphins; porpoises; narwhals
    synonyms: blower, cetacean mammal
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    any of the larger cetacean mammals having a streamlined body and breathing through a blowhole on the head
    baleen whale, whalebone whale
    whale with plates of whalebone along the upper jaw for filtering plankton from the water
    toothed whale
    any of several whales having simple conical teeth and feeding on fish etc.
    Monodon monoceros, narwal, narwhal, narwhale
    an Arctic cetacean, the male of which has a long ivory tusk
    a spouting whale
    type of:
    aquatic mammal
    whales and dolphins; manatees and dugongs; walruses; seals
  2. adjective
    of or relating to whales and dolphins etc
    synonyms: cetaceous
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