dolphin

American  

[dawl-fin, dol-] / ˈdɔl fɪn, ˈdɒl- /

noun

1. 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.

2. Also called dolphinfish, mahimahi.  Also called pompano dolphin.  either of two large, slender fishes, Coryphaena hippurus or C. equisetis, of warm and temperate seas.

3. Nautical.

   1. a pile, cluster of piles, or buoy to which a vessel may be moored in open water.

   2. a cluster of piles used as a fender, as at the entrance to a dock.

   3. a pudding fender at the nose of a tugboat or on the side of a vessel.

4. Astronomy. Dolphin, the constellation Delphinus.

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dolphin British  

/ ˈdɒlfɪn /

noun

1. 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

2. 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

3. 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

4. nautical a post or buoy for mooring a vessel

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Etymology

Origin of dolphin

First recorded in 1300–50; Middle English dolphyn, from Old French daulphin, from Old Provençal dalfin, from unattested Vulgar Latin dalfīnus, Latin delphīnus, from Greek delphī́n

Explanation

Dolphins are smart, sociable aquatic mammals that live in every ocean on the planet. Scientists aren't sure why they do it, but dolphins are known for leaping above the surface of the water as they swim. Dolphins are one of the most commonly recognized and beloved sea creatures, in part because they are gregarious and friendly. Their playful nature and intelligence have brought dolphins into close contact with humans, not always to their benefit. Scientists have learned that dolphins live longer, happier lives when they're not in captivity, so you're less likely to see dolphins at an aquarium than in the past. Dolphins are mammals, giving birth to live babies, which may explain the Greek root of dolphin, delphys, meaning "womb."

Example Sentences

The first suspected case of a grey seal killing a common dolphin has been recorded in Wales.

From BBC • Mar. 2, 2026

The dolphin carcass has been sent for further examination, although test results could take up to six months.

From BBC • Mar. 2, 2026

Although initial reports show the measure may be helping, Rouby suggested that adjusting the ban's timing based on dolphin migration patterns could make it more effective.

From Science Daily • Oct. 22, 2025

For many nature enthusiasts, few scenes are as distressing as finding a stranded whale or dolphin lying helpless on the beach.

From Science Daily • Oct. 11, 2025

I have never been to Miami and never seen a dolphin.

From "Everything Sad Is Untrue" by Daniel Nayeri