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

Part of the county’s justification for terminating the Seaquarium’s lease rests on maintenance issues, including code violations for the tank where manatees live and the stadium where dolphins perform. —Douglas Hanks, Miami Herald, 19 Apr. 2024

Dead dolphins aren’t observable, and living dolphins who survive attacks may not always bear scars. —Katie Liu, Discover Magazine, 17 Apr. 2024

Billions of crabs disappeared in the northern Pacific; sea lions and dolphins are washing up sick; iconic coral reefs are undergoing mass bleaching. —Rachel Ramirez, CNN, 15 Apr. 2024

Four such dolphins remain intact in the Patapsco River. —Caitlin Thompson, NPR, 4 Apr. 2024

Still, dolphins don’t always work – as the Key Bridge disaster demonstrates. —Cnn.com Wire Service, The Mercury News, 3 Apr. 2024

Passed by primates, dolphins, elephants and even certain fish, the test has been thought to measure social intelligence. —Christian Thorsberg, Smithsonian Magazine, 4 Apr. 2024

Critics say that noise could disrupt marine mammals such as whales and dolphins, while plumes of sediment, potentially containing toxic compounds, kicked up by equipment on the seabed may disperse, harming midwater ecosystems, according to recent research. —Katie Hunt, CNN, 3 Apr. 2024

Mammals are not solely terrestrial; some are fully aquatic, including whales and dolphins, the University of Michigan Museum of Zoology reports. —Olivia Munson, USA TODAY, 1 Apr. 2024

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