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

Video footage captured by Capt. Evan Brodsky of Monterey Bay Whale Watch on Friday shows the Risso's dolphins, also called gray dolphins, breaching and gliding in Carmel Bay, just off the central coast of California. —Saman Shafiq, USA TODAY, 30 Jan. 2025

The sighting was rare: Risso’s dolphins typically travel in groups of only 10 to 30 animals, according to the National Oceanic and Atmospheric Administration. —Nbc Bay Area Staff, NBC News, 29 Jan. 2025

Risso’s dolphins, which can weigh as much as 1,100 pounds and reach as long as 13 feet, typically travel in groups of 10 to 30 animals, according to the National Oceanic and Atmospheric Administration. —Stephen Sorace, Fox News, 29 Jan. 2025

In 2023, rare pink dolphins were spotted swimming off the coast of Louisiana. —CBS News, 29 Jan. 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