dol·phin / ˈdälfin; ˈdôl-/ • n. 1. a small gregarious and highly intelligent toothed whale that typically has a beaklike snout and a curved fin on the back. Dolphins inhabit seas (family Delphinidae) and rivers (family Platanistidae). ∎  a dolphinlike creature depicted in heraldry or art, typically with an arched body and fins like a fish. 2. (also dolphinfish) another term for mahimahi. 3. a bollard, pile, or buoy for mooring. 4. a structure for protecting the pier of a bridge or other structure from collision with ships.

dolphin Family of small-toothed aquatic whales, there are salt and freshwater species. The best-known are the dark blue-backed common dolphin, the blue-grey bottle-nosed and the killer whale. Larger than a porpoise, a dolphin has a distinct beak and slender body, a tail fin for propulsion, and a dorsal fin for steering. A dolphin breathes through a single blowhole, and can remain underwater for 15 minutes. It is the fastest and most agile of the whales, achieving speeds up to 39km/h (24mph) and leaps of 9m (30ft). Dolphins swim in large, hierarchically organized schools, feeding on fish and crustacea. Their intelligence and playful behaviour have contributed to a wealth of maritime literature and mythology. They communicate through a complex language and map their environment by echolocation. Dolphins have a gestation period of 12 months, and the mother nurtures her calf for the first two years of life. Length: to 4m (13ft). Family Delphinidae; species Tursiops truncatus.

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dolphin XIII. Three types of form have been current:
i. delfyn, delphin — L. delphīnus — Gr. delphís, -īn-;

ii. dalphyn — OF. daulphin (see DAUPHIN);

iii. dolfyn, dolphin, app. Eng. alts. of (ii).

dolphin used for a dolphin-like creature depicted in heraldry or art, typically with an arched body and fins like a fish; in early Christian art, used as an emblem of love, diligence, or swiftness.

dolphin (Delphinus) See DELPHINIDAE.