noun

1. any of two widespread families (Platanistidae and Delphinidae) of toothed whales having high levels of intelligence and usually a beaklike snout
2. any of a percoid family (Coryphaenidae) of marine game fishes with colors that brighten and change when the fish is taken out of the water
3. Naut. a buoy, pile, or, esp., a cluster of piles for mooring a vessel

Etymology: ME dolfin < OFr dalphin < VL dalfinus, for L delphinus < Gr delphinos, gen. of delphis (< IE base *gwelbh-): so named from its shape