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

They say the barriers kill local endangered species like the Indian Ocean humpback dolphin and the leatherback turtle, and they’re not that good at keeping out sharks.

From The Wall Street Journal ● May 31, 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

Despite such figures, past surveys suggested that dolphin numbers in the area were stable.

From Science Daily ● Oct. 22, 2025

It reminded me of a fact from Jenna’s presentation—that a mother dolphin does not stop swimming for the first several weeks of her newborn’s life.

From "The Thing About Jellyfish" by Ali Benjamin

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

At roughly 5 feet long, it is the smallest member of the cetacean group, which includes whales, dolphins and porpoises.

From Science Daily ● Jun. 17, 2026

A report spokesperson said the government had been slow to develop plans to reduce bycatch and rules prevent fishermen near UK shores from putting acoustic devices on their nets to deter dolphins.

From BBC ● Jun. 10, 2026

The Navy has previously trained External link bottlenose dolphins and sea lions, chiefly for reconnaissance and recovering objects like undersea mines.

From Barron's ● May 14, 2026

There are dolphins and parrotfish, hawksbill turtles and shovelnose sharks.

From "Dreaming in Cuban" by Cristina García