dolphin

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of various marine toothed whales of the family Delphinidae, having a beaklike snout, a curved dorsal fin, and a slender streamlined body.
• noun 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.
• noun A buoy, pile, or group of piles used for mooring boats.
• noun A group of piers used as a fender at a dock.

from The Century Dictionary.

• noun The popular name of the cetaceous mammals of the family Delphinidæ and genus Delphinus, most of which are also known as and more frequently called porpoises, this word being interchangeable with dolphin.
• noun A general and popular name of fish of the family Coryphænidæ: so called from some con-fusion with the mammals of the same name.
• noun In Gr. antiquity, a ponderous mass of lead or iron suspended from a special yard on a naval vessel, and, if opportunity presented, let fall into the hold of a hostile ship to sink her by breaking through her bottom.
• noun Nautical: A spar or buoy made fast to an anchor, and usually supplied with a ring to enable vessels to ride by it.
• noun A mooring-post placed at the entrance of a dock.
• noun In early artillery, a handle cast solid on a cannon.
• noun [capitalized] In astronomy, an ancient northern constellation, Delphinus (which see).
• noun In architecture, a technical term applied to the pipe and cover at a source for the supply of water.
• noun In Christian archæol., an image or representation of a dolphin, constituting an emblem of love, diligence, and swiftness.
• noun Same as dauphin.
• noun In lumbering, a cluster of piles to which a boom is secured. [U. S.]
• noun Same as dolphin-fly.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Zool.) A cetacean of the genus Delphinus and allied genera (esp. Delphinus delphis); the true dolphin.
• noun (Zool.) 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.
• noun (Gr. Antiq.) A mass of iron or lead hung from the yardarm, in readiness to be dropped on the deck of an enemy's vessel.
• noun A kind of wreath or strap of plaited cordage.
• noun A spar or buoy held by an anchor and furnished with a ring to which ships may fasten their cables.
• noun A mooring post on a wharf or beach.
• noun A permanent fender around a heavy boat just below the gunwale.
• noun (Gun.) In old ordnance, one of the handles above the trunnions by which a cannon was lifted.
• noun (Astron.) A small constellation between Aquila and Pegasus. See Delphinus, n., 2.
• noun (Zoöl.) the black, bean, or collier, Aphis (Aphis fable), destructive to beans.
• noun (Naut.) a short vertical spar under the bowsprit.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun 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.
• noun A carnivorous aquatic mammal inhabiting mostly in the shallower seas of the continental shelves, famed for its intelligence and occasional willingness to approach humans.
• noun A fish, the mahi-mahi or dorado, scientific name Coryphaena hippurus, with a dorsal fin that runs the length of the body, also known for iridescent coloration.
• noun The dauphin, eldest son of the kings of France.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun any of various small toothed whales with a beaklike snout; larger than porpoises
• noun large slender food and game fish widely distributed in warm seas (especially around Hawaii)