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

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

• dolphin 1a

Examples of dolphin in a Sentence

Recent Examples on the Web

Another video posted by CNN correspondent Omar Jimenez on X showed the group of dolphins swimming near the capsule shortly after landing alongside a rescue crew heading over to check on the spacecraft. —Escher Walcott, People.com, 19 Mar. 2025

Curious dolphins come to inspect the capsule A pod of dolphins were spotted near by the capsule after its successful splashdown on Tuesday. —Amanda Castro, Newsweek, 18 Mar. 2025

The former is at work on a coastal protection project, Patagonia Azul, on the shores of Chubut Province, Argentina, where dolphins, seals, and whales congregate. —Travel + Leisure Editors, Travel + Leisure, 18 Mar. 2025

Watch: Fishermen steer 900-pound dolphin to safety Video footage from the incident shows the dolphin lying on the boat as one of the men steers the boat while another waters it with a hose. —Saman Shafiq, USA TODAY, 6 Mar. 2025

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