- any of several chiefly marine, cetacean mammals of the family Delphinidae, having a fishlike body, numerous teeth, and the front of the head elongated into a beaklike projection.
- Also called dolphinfish, mahimahi, pompano dolphin. either of two large, slender fishes, Coryphaena hippurus or C. equisetis, of warm and temperate seas.
- a pile, cluster of piles, or buoy to which a vessel may be moored in open water.
- a cluster of piles used as a fender, as at the entrance to a dock.
- a pudding fender at the nose of a tugboat or on the side of a vessel.
- (initial capital letter) Astronomy. the constellation Delphinus.
- any of various marine cetacean mammals of the family Delphinidae, esp Delphinus delphis, that are typically smaller than whales and larger than porpoises and have a beaklike snout
- river dolphin any freshwater cetacean of the family Platanistidae, inhabiting rivers of North and South America and S Asia. They are smaller than marine dolphins and have a longer narrower snout
- Also called: dorado either of two large marine percoid fishes, Coryphaena hippurus or C. equisetis, that resemble the cetacean dolphins and have an iridescent coloration
- nautical a post or buoy for mooring a vessel
mid-14c., from Old French daulphin, from Medieval Latin dolfinus, from Latin delphinus “dolphin,” from Greek delphis (genitive delphinos) “dolphin,” related to delphys “womb,” perhaps via notion of the animal bearing live young, or from its shape, from PIE *gwelbh-. Popularly applied to the dorado from late 16c.