Definitions for "Cetacea"
An order of marine mammals, including the whales. Like ordinary mammals they breathe by means of lungs, and bring forth living young which they suckle for some time. The anterior limbs are changed to paddles; the tail flukes are horizontal. There are two living suborders:
An Order of marine mammals. The suborder Odontocetti includes dolphins, killer whales and toothed whales. Many of the great whales (such as the blue whale) belong to a different suborder (baleen whales or Mysticetti).
The large order of animals that includes all whales and dolphins.