dol·​phin | \ ˈdäl-fən How to pronounce dolphin (audio) , ˈdȯl- \

Definition of dolphin

1a : any of various small marine toothed whales (family Delphinidae) with the snout more or less elongated into a beak and the neck vertebrae partially fused

Note: While not closely related, dolphins and porpoises share a physical resemblance that often leads to misidentification. Dolphins typically have cone-shaped teeth, curved dorsal fins, and elongated beaks with large mouths, while porpoises have flat, spade-shaped teeth, triangular dorsal fins, and shortened beaks with smaller mouths.

b : any of several related chiefly freshwater toothed whales (as of the families Platanistidae and Iniidae) : river dolphin
3 capitalized : delphinus
4 : a spar or buoy for mooring boats also : a cluster of closely driven piles used as a fender for a dock or as a mooring or guide for boats

Illustration of dolphin

Illustration of dolphin

dolphin 1a

Examples of dolphin in a Sentence

Recent Examples on the Web The larger creature—a dolphin-like reptile known as an ichthyosaur—then fossilized with the smaller animal in its belly. Jason Bittel, National Geographic, "13-foot marine predator found inside another's belly in shocking fossil 'turducken'," 20 Aug. 2020 After this ancient dolphin went extinct about 23 million years ago, shark-toothed dolphins and giant killer sperm whales evolved to occupy Ankylorhiza's position within 5 million years. Kristen Rogers, CNN, "An extinct giant dolphin behaved like a killer whale, study finds," 9 July 2020 The oceanic dolphin species can grow to around 20 feet. Washington Post, "380 pilot whales dead in one of the worst mass strandings in Australia’s history," 23 Sep. 2020 The water resort also offers a Premium Proposal Celebration Package that includes the aforementioned dolphin experience, plus a photo package, tote and private cabana with a floral engagement and ring display. Kathleen Christiansen,, "9 very Orlando proposals and gender reveals," 18 Sep. 2020 Hopefully, this research and the dolphin’s latest return will spur more people into action to save them. Stacey Leasca, Travel + Leisure, "Adorable Pink Dolphins Are Returning to Hong Kong Due to Lower Ferry Traffic," 16 Sep. 2020 Northern Territory government whale and dolphin scientist Carol Palmer said there was at least one whale still in the river on the weekend. Rod Mcguirk, Star Tribune, "Australians hope to save whale from crocodile-infested river," 14 Sep. 2020 The extinct dolphin also had incisors that protruded forward like tusks, which might have been used for ramming its victims. Alex Fox, Smithsonian Magazine, "Giant Extinct Dolphin May Have Hunted Other Whales," 14 July 2020 The ichthyosaur is of the genus Guizhouichthyosaurus and would have looked something like a large dolphin with long slender jaws. Alex Fox, Smithsonian Magazine, "This 15-Foot Ichthyosaur Died With a 13-Foot Meal in Its Stomach," 24 Aug. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'dolphin.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of dolphin

14th century, in the meaning defined at sense 1a(1)

History and Etymology for dolphin

Middle English delphyn, dolphyn, from Anglo-French delphin, alteration of Old French dalfin, from Medieval Latin dalfinus, alteration of Latin delphinus, from Greek delphin-, delphis; akin to Greek delphys womb, Sanskrit garbha

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Time Traveler for dolphin

Time Traveler

The first known use of dolphin was in the 14th century

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Statistics for dolphin

Last Updated

21 Oct 2020

Cite this Entry

“Dolphin.” Dictionary, Merriam-Webster, Accessed 29 Oct. 2020.

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More Definitions for dolphin


How to pronounce dolphin (audio)

English Language Learners Definition of dolphin

: a small usually gray whale that has a pointed nose


dol·​phin | \ ˈdäl-fən How to pronounce dolphin (audio) , ˈdȯl- \

Kids Definition of dolphin

1 : a small whale with teeth and a long nose
2 : either of two large fish usually of warm seas that are often used for food

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More from Merriam-Webster on dolphin

Nglish: Translation of dolphin for Spanish Speakers

Britannica English: Translation of dolphin for Arabic Speakers Encyclopedia article about dolphin

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