dolphin

noun dol·phin \ ˈdäl-fən , ˈdȯl- \

Updated on: 18 Apr 2018

Definition of dolphin

1 a : 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

2 : dolphinfish

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

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Recent Examples of dolphin from the Web

Her dark green silks bear the images of two jumping dolphins.

— sun staff reports, baltimoresun.com, "Zanclus makes a splash to win My Lady's Manor in first race of Maryland timber triple crown," 14 Apr. 2018
With medical clearance, the dolphins were released into the waters of West Dennis Beach.

— alana levene, BostonGlobe.com, "3 dolphins stranded in Brewster released back into the sea," 29 Mar. 2018
As Gearty tells Geggel, there are also smaller species of seals and many species of dolphins that don’t reach 1,000 pounds.

— jason daley, Smithsonian, "Why Are Whales So Massive? It’s All About Energy," 27 Mar. 2018
It is known for unconventional treatments such as swimming with dolphins and social events where veterans mix with children.

— eli rosenberg, Washington Post, "Gunman was treated at veterans facility before he killed three workers there, officials say," 10 Mar. 2018
There's lots to do in Cozumel: an island tour, swimming with dolphins, archaeological sites, tequila factory and mescal bars, a 45-minute ferry ride to the mainland.

— marjorie miller, chicagotribune.com, "Picking the right home rental for a Mexico beach vacation," 15 Feb. 2018
Out front was a fountain with life-size statues of dolphins.

— will higgins, Indianapolis Star, "A dominatrix, a 'Broom Guy,' a 'Beeper King': Meet 23 Hoosier oddballs and characters," 8 Jan. 2018
Terrestrial species like primates and rodents have been known to commit infanticide, and the behavior has been infrequently observed among dolphins.

— brigit katz, Smithsonian, "A Male Orca and Its Mother Worked Together to Kill a Newborn Calf," 27 Mar. 2018
In Barataria Bay, salinity levels greater than eight parts per thousand were found to be critical for suitable dolphin habitat.

— mark schleifstein, NOLA.com, "Feds grant waiver of law protecting dolphins for proposed sediment diversions," 23 Mar. 2018

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.

Illustration of dolphin

Origin and Etymology of 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

NEW! Time Traveler

First Known Use: 14th century

in the meaning defined at sense 1a(1)

See Words from the same year