: 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
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
Examples are automatically compiled from online sources to
show current usage.Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Lost or abandoned underwater fishing nets continue to trap everything in their path, from fish to turtles and dolphins, and harm delicate ecosystems.—Claire Poole, Forbes.com, 30 Mar. 2025 The dolphins scattered and the men returned empty-handed.—Prianka Srinivasan Matthew Abbott, New York Times, 26 Mar. 2025 At least 50 dolphins have been found poisoned and stranded on beaches, though domoic acid ingestion is typically a death sentence for them.—Ryan Fonseca, Los Angeles Times, 25 Mar. 2025 After the SpaceX capsule splashed down in the Atlantic Ocean, they were greeted by a pod of dolphins swimming nearby.—Alex Knapp, Forbes, 21 Mar. 2025 See All Example Sentences for dolphin
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)
Time Traveler
The first known use of dolphin was
in the 14th century
Share