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

This year’s training camp will feature unique Dolphins giveaways to the first 1,000 fans every day and food trucks from local restaurants will be on site. — Omar Kelly july 8, Miami Herald, 8 July 2026

Hargreaves may not have known about the Chiefs’ Wild Card win over the Dolphins in 2024 when a howling wind made the negative-4 degree temperature feel all the worse. — Pete Grathoff, Kansas City Star, 6 July 2026

Dolphins are frequently spotted just offshore, while coastal birds can often be seen soaring above the beaches. — Abby Price, Southern Living, 6 July 2026

In the forests and on the beaches, keep your eyes peeled for native wildlife like Roosevelt elk, marmots, orcas, gray whales, humpbacks, dolphins, sea lions, and bald eagles. — Zoe Baillargeon, Travel + Leisure, 5 July 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