dolphin

American  

[dawl-fin, dol-] / ˈdɔl fɪn, ˈdɒl- /

noun

dolphins plural

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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Other Word Forms

Noun Inflected Forms

• dolphins
  plural

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

See Examples For:

dolphin dolphins

Israel’s Army Radio reported that Hamas claims to have captured an Israeli spy dolphin, equipped with surveillance gear, off the coast of Gaza.

From The Wall Street Journal ● May 14, 2026

He wouldn’t say if the U.S. had dolphin assets in the water.

From Barron's ● May 6, 2026

"We've always found it tricky to understand how grey seals would kill a healthy dolphin or porpoise," Langley said.

From BBC ● Mar. 2, 2026

Under ideal conditions, common dolphin numbers can increase by about 4% per year, meaning that growth in 2019 was likely only around 1.6%.

From Science Daily ● Oct. 22, 2025

Percy had never considered just how vicious dolphin teeth looked.

From "The Mark of Athena" by Rick Riordan

On a boat off the coast of California, Sara Lesser gazes wistfully at dozens of dolphins playing in the vessel's wake.

From Barron's ● Jul. 27, 2026

I picked him up at Los Angeles International Airport and took him straight to Zuma Beach for a picnic, where we watched dolphins jumping in the waves while the seagulls stole our potato chips.

From Los Angeles Times ● Jun. 26, 2026

In contrast, fishermen working with dolphins may interpret different dolphin behaviors as cues for when to cast their nets, and those signals can vary from one region to another.

From Science Daily ● Jun. 20, 2026

She said previous studies had focussed more on porpoises but the picture "remained unclear" for common dolphins.

From BBC ● Jun. 10, 2026

Frigate birds soared overhead, and a pod of dolphins rolled past us, herding mullet.

From "Flush" by Carl Hiaasen