dolphin

noun

dol·​phin ˈdäl-fən 

ˈdȯl-

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

Dolphin : 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

• dolphin 1a

Examples of dolphin in a Sentence

Recent Examples on the Web

Thursday’s win kept the Dolphins alone atop the Western League standings at 8-0, 2½ games ahead of Fairfax with only four left. —Steve Galluzzo, Los Angeles Times, 30 Jan. 2026

Offensively, the Dolphins have Bobby Slowik as offensive coordinator, Nathaniel Hackett as quarterbacks coach, Ladell Betts as running backs coach, Tyke Tolbert as wide receivers coach and Zach Yenser as offensive line coach. —David Furones, Sun Sentinel, 30 Jan. 2026

The denial aligned with Canada’s 2019 ban on whale and dolphin captivity, though Marineland’s animals were exempt under grandfathering provisions. —Moná Thomas, PEOPLE, 29 Jan. 2026

Dolphins talk to Rutledge Keylan Rutledge has been one of the top offensive line prospects at the Senior Bowl. —Miami Herald, 29 Jan. 2026

Word History

Etymology

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

First Known Use

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

Phrases Containing dolphin

• bottle-nosed dolphin
• bottlenose dolphin
• dolphin striker
• Risso's dolphin
• river dolphin
• spinner dolphin

Kids Definition

dolphin

noun

dol·​phin ˈdäl-fən 

ˈdȯl-

1

a

: any of various small whales with teeth and a long nose

b

: porpoise sense 1

2

: either of two active saltwater food fishes noted for their brilliant coloring