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

Some of the winless teams aren't too surprising, with Miami there as part of a rebuild in a season when the Dolphins are carrying a record $184 million in dead money charges on the salary cap. — ABC News, 7 Oct. 2026

Three days after Chop Robinson had a stellar game against Minnesota, another former Dolphins first-rounder, defensive tackle Kenneth Grant, returned to practice Wednesday, hoping to raise his game after a pedestrian rookie season. — Barry Jackson, Miami Herald, 7 Oct. 2026

During a live play, Dolphins running back Ollie Gordon blocked Vikings' linebacker Eric Wilson into Hill, knocking the referee down. — Alejandro Avila Outkick, FOXNews.com, 5 Oct. 2026

The Chiefs had won a Super Bowl, lost one and were coming off a stunning AFC Championship Game collapse when Tyreek Hill was traded to the Dolphins in March 2022. — Pete Grathoff, Kansas City Star, 5 Oct. 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