Dolphin vs. Porpoise

Dolphin is the common name of aquatic mammals within the infraorder Cetacea. The term dolphin usually refers to the extant families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), named Iniidae (the New World river dolphins), and Pontoporiidae (the brackish dolphins), and the extinct Lipotidae (baiji or Chinese river dolphin).

Porpoises are a group of fully aquatic marine mammals, similar in appearance to a dolphin, all of which are classified under the family Phocoenidae, parvorder Odontoceti (toothed whales). They are, however, more closely related to narwhals and belugas than to the true dolphins.

Any of various marine toothed whales of the family Delphinidae, having a beaklike snout, a curved dorsal fin, and a slender streamlined body.

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 toothed whales inhabiting rivers and estuaries in South America and South Asia, having a long narrow beak, broad flippers, a flexible neck, and usually a reduced dorsal fin. A species native to the Yangtze River is thought to be extinct. Also called river dolphin.

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

See dolphinfish.

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

See pompano dolphinfish.

Any small dolphin.

A buoy, pile, or group of piles used for mooring boats.

(intransitive) Said of an air-breathing aquatic animal such as a porpoise or penguin: To repeatedly jump out of the water to take a breath and dive back in a continuous motion.

A group of piles used as a fender, as at a dock or around a bridge pier.

(intransitive) Said of an aircraft: to make a series of plunges when taking off or landing; or of a watercraft: to successively plunge up and down in the water.

A carnivorous aquatic mammal in one of several families of order Cetacea, famed for its intelligence and occasional willingness to approach humans.

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.

Tursiops truncatus, (Atlantic bottlenose dolphin) the most well-known species.

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

A fish, the mahi-mahi or dorado, Coryphaena hippurus, with a dorsal fin that runs the length of the body, also known for iridescent coloration.

any of several small gregarious cetacean mammals having a blunt snout and many teeth

(heraldry) A depiction of a fish, with a broad indented fin, usually embowed.

The dauphin, eldest son of the kings of France.

(history) A mass of iron or lead hung from the yardarm, in readiness to be dropped through the deck and the hull of an enemy's vessel to sink it.

(nautical) A kind of wreath or strap of plaited cordage.

(nautical) A spar or buoy held by an anchor and furnished with a ring to which ships may fasten their cables.

(nautical) A mooring post on a wharf or beach.

(nautical) A permanent fender designed to protect a heavy boat or coastal structure from the impact of large floating objects such as ice or floating logs.

One of the handles above the trunnions by which a gun was lifted.

(nautical) A man-made semi submerged maritime structure, usually installed to provide a fixed structure for temporary mooring, to prevent ships from drifting to shallow water or to serve as base for navigational aids.

A cetacean of the genus Delphinus and allied genera (esp. Delphinus delphis); the true dolphin.

The Coryphæna hippuris, a fish of about five feet in length, celebrated for its surprising changes of color when dying. It is the fish commonly known as the dolphin. The term is also applied to the related Coryphaena equisetis. Called also dolphinfish and (especially in Hawaii) mahimahi. See also dolphinfish and Coryphænoid.

A mass of iron or lead hung from the yardarm, in readiness to be dropped on the deck of an enemy's vessel.

A kind of wreath or strap of plaited cordage.

In old ordnance, one of the handles above the trunnions by which a cannon was lifted.

large slender food and game fish widely distributed in warm seas (especially around Hawaii)

any of various small toothed whales with a beaklike snout; larger than porpoises