What does dolphin mean?
A dolphin is a highly intelligent aquatic mammal belonging to the family Delphinidae, characterised by a sleek, streamlined body, a prominent dorsal fin, a beaklike rostrum, and remarkable social behaviour. Dolphins inhabit oceans and some rivers worldwide, living in groups called pods, communicating through clicks and whistles, and displaying well-documented playfulness toward humans and other species. The word also has two less common senses: it names the dolphinfish (mahi-mahi), a large edible ocean fish entirely unrelated to the mammal, and, in nautical engineering, a cluster of pilings driven into a seabed or riverbed to guide ships or serve as a mooring point. Because of their intelligence and charisma, dolphins hold strong positive connotations and feature prominently in conservation campaigns, marine tourism, and popular culture. The word derives ultimately from Greek via Latin and Old French.
A highly intelligent marine mammal of the family Delphinidae, with a streamlined body, beaklike snout, and dorsal fin, known for playfulness and social behaviour.
"We watched a dolphin surf the wake behind our boat for nearly half an hour."
This is by far the dominant sense in modern usage.
The dolphinfish or mahi-mahi, a large brightly coloured oceanic food fish unrelated to the marine mammal.
"The restaurant advertised fresh dolphin caught that morning off the Florida coast."
Usually clarified as 'dolphinfish' or called 'mahi-mahi' to avoid confusion with the mammal.
A structure of piles driven into a riverbed or seabed, used to moor ships or guide navigation.
"The ferry tied up against a timber dolphin at the edge of the channel."
Technical maritime term, rarely encountered outside harbour engineering contexts.
Regular plural. When referring collectively, 'pod of dolphins' is the standard grouping term. For the fish sense, 'dolphinfish' is often treated as invariant, though 'dolphins' remains acceptable.
"Hundreds of dolphins gathered offshore during the annual sardine run."
The word 'dolphin' comes from the Greek for 'womb' — ancient Greeks saw its shape as resembling a fish with child-bearing form, and named it 'the fish with a womb.'
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of dolphin
The word 'dolphin' entered Middle English from Old French 'dauphin', which derived from Latin 'delphinus', itself borrowed from Greek 'delphis'. The Greek term is generally linked to 'delphys', meaning 'womb', possibly reflecting the animal's shape or its reputation for bearing live young. The same Greek root gives us the plant name 'delphinium' and the French royal title 'dauphin'.
How dolphin is actually used
In everyday use, 'dolphin' almost always means the mammal; when referring to the fish, speakers usually say 'dolphinfish' or the Hawaiian name 'mahi-mahi' to avoid confusion. The nautical engineering sense (a mooring structure) is technical and rare outside maritime contexts.
Easily confused with dolphin
Porpoises are a different family of small toothed whales (Phocoenidae) with blunt snouts and spade-shaped teeth, whereas dolphins typically have longer beaks and conical teeth.
Dauphin is the historical title of the eldest son of the French king and shares an etymological root with dolphin, but refers to royalty rather than the animal.