Illustration of dolphin
- dolphin 1a
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
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
Examples of dolphin in a Sentence
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Their analysis revealed that 71 of the tools were made from the bones of cetaceans, the group of marine mammals that includes whales, dolphins and porpoises.
—
Sarah Kuta, Smithsonian Magazine, 28 May 2025
Much else about the dolphins, including the specifics of their reproductive habits, remains unknown.
—Brendan Rascius, Miami Herald, 28 May 2025
Those who live along the banks of a southeast canal in Cape Coral are used to a peaceful day-to-day life, with the exception of an odd dolphin or stingray sighting.
—Rachel Raposas, People.com, 19 May 2025
The video featured a dolphin swimming while wearing Hill’s No. 10, drawing a siren from a Coast Guard boat helmed by an officer crossing his arms with a look of disapproval.
—Chuck Schilken, Los Angeles Times, 15 May 2025
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Sarah Kuta, Smithsonian Magazine, 28 May 2025
Much else about the dolphins, including the specifics of their reproductive habits, remains unknown.
—Brendan Rascius, Miami Herald, 28 May 2025
Those who live along the banks of a southeast canal in Cape Coral are used to a peaceful day-to-day life, with the exception of an odd dolphin or stingray sighting.
—Rachel Raposas, People.com, 19 May 2025
The video featured a dolphin swimming while wearing Hill’s No. 10, drawing a siren from a Coast Guard boat helmed by an officer crossing his arms with a look of disapproval.
—Chuck Schilken, Los Angeles Times, 15 May 2025
See All Example Sentences for dolphin
Cite this Entry
“Dolphin.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/dolphin. Accessed 3 Jun. 2025.
Copy CitationKids Definition
dolphin
noun
dol·phin
ˈdäl-fən 
ˈdȯl-
1
a
: any of various small whales with teeth and a long nose
b
2
: either of two active saltwater food fishes noted for their brilliant coloring
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