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
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
Cite this Entry
“Dolphin.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/dolphin. Accessed 5 Aug. 2026.
Copy CitationLove words? Need even more definitions?
Merriam-Webster unabridged
