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

Visitors can walk 7 miles of trails and see 140 bird species and animals such as manatees, dolphins, alligators, otters, bobcats, sea turtles and gopher tortoises. —Usa Today Network, USA Today, 10 June 2026

Whereas veteran players will begin their time off later this week, the Dolphins will keep rookies in the building until early next week. —Barry Jackson, Miami Herald, 9 June 2026

Duck initially made the Dolphins’ 2024 roster as an undrafted rookie. —David Furones, Sun Sentinel, 9 June 2026

The game plan is to hit first, before the defense can react and adjust, something the Dolphins often did well with McDaniel as their head coach, Barry coaching the offensive line and Tua Tagovailoa quarterbacking an up-tempo offense. —Elliott Teaford, Oc Register, 8 June 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