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 Lifeguards were able to free the dolphin from the ropes and called in the Clearwater Marine Aquarium's Rescue Team, which attempted to reconnect the calf with its mother. Amanda Jackson, CNN, 20 July 2022 Biologists are working alongside NOAA to determine how to protect the dolphin. Stephanie Wenger,, 31 May 2022 Clooney, in one scene, even gets bit by a dolphin while weary of sharks. Benjamin Vanhoose,, 29 June 2022 So there's a big tonal gearshift between some of the darker scenes in the show and then scenes like when the Deep's trying to save a dolphin from Oceanland and accidentally ejects it through the windshield of his car. Nojan Aminosharei, Men's Health, 24 June 2022 Enlarge / Being a dolphin's actually not a great thing. Corey Gaskin, Ars Technica, 22 June 2022 Corpus Christi: Officials are warning beachgoers to stay away from an overly friendly dolphin off North Padre Island. From Usa Today Network And Wire Reports, USA TODAY, 1 June 2022 It is known that in captivity signature whistles happen most often when a dolphin is isolated from its group. Sarah Sloat, NBC News, 26 May 2022 When a dolphin is stranded on the beach, Whitehead explained, it is usually injured or sick and could be having difficulty breathing. Washington Post, 6 May 2022 See More

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.

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

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Last Updated

30 Jul 2022

Cite this Entry

“Dolphin.” Dictionary, Merriam-Webster, Accessed 10 Aug. 2022.

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More Definitions for dolphin


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

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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