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

The Dolphins have voices like linebacker Jordyn Brooks, defensive tackle Zach Sieler, center Aaron Brewer and left tackle Patrick Paul as the youth comes into its own. —David Furones, Sun Sentinel, 28 Apr. 2026

Even after filling several roster holes in the NFL Draft, the Dolphins exited the weekend with a glaring need at safety and an uneasy situation on the edge, at wide receiver and at tight end. —Barry Jackson, Miami Herald, 27 Apr. 2026

Stephen Ross, majority owner of both the Miami Dolphins and the Miami Grand Prix, said his three-day F1 race sells more tickets than the Dolphins do in season tickets. —Maxwell Adler, Vanity Fair, 27 Apr. 2026

One of Olson’s predecessors as Central quarterback, Jake Dolegala, had NFL opportunities with the Bengals, Patriots, Packers and Dolphins in 2019, ’20 and ’21, and has been playing in the CFL the last several years. —Dom Amore, Hartford Courant, 27 Apr. 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