Emily Dickinson Lexicon

DOL'PHIN, n. [L. delphin or delphinus; Gr. δελφιν; Ir. deilf; Fr. dauphin; Sp. delfin; It. delfino; Arm. daofin, dolfin; W. dolfyn, from dolf, a curve or winding.]

1. The popular name of several species of Delphinus, a genus of cetaceous mammalia comprehending, according to some naturalists, the dolphin proper, the sword-fish, the porpess, the grampus, &c. But the fish to which seamen give this name, is the Coryphæna hippuris of Linnæus. – Dict. of Nat. Hist.
2. In ancient Greece, a machine suspended over the sea, to be dropped on any vessel passing under it. Mitford.