porpoise

Any of various marine toothed whales of the genus Phocoena and related genera, characteristically having a blunt snout and a triangular dorsal fin. Porpoises are placed either in their own family, Phocoenidae, or with the dolphins in the family Delphinidae.

Any of several related aquatic mammals, such as the dolphins.

A small toothed cetacean of the family Delphinidæ and subfamily Delphiminæ, and especially of the genus Phoeæna, of which there are several species, the best-known being P. communis, which attains a length of about 5 feet and has a blunt head not produced into a long beak, and a thick body tapering toward the tail.

Any small cetacean of the genus Phocæna, especially Phocæna communis, or Phocæna phocæna, of Europe, and the closely allied American species (Phocæna Americana). The color is dusky or blackish above, paler beneath. They are closely allied to the dolphins, but have a shorter snout. Called also harbor porpoise, herring hag, puffing pig, and snuffer.

A true dolphin (Delphinus); — often so called by sailors.

a North American porpoise (Lagenorhynchus acutus), larger than the common species, and with broad stripes of white and yellow on the sides. See Illustration in Appendix.

A small cetacean of the family Phocoenidae, related to whales and dolphins.

Any small dolphin.

Said of an aircraft: to make a series of plunges when taking off or landing.