any of several species of small gregarious toothed marine whales with the snout elongated into a beak: family Delphinidae
any of several species of similar freshwater whales: family Platanistidae
a large food fish of warm seas that has spiny fins: Coryphaena hippurus
a spar or buoy for mooring boats
[Middle English via Old French dalfin and Latin delphinus from Greek delphin-, delphis dolphin]