But″ter‐fly′ (�), n.; pl.Butterflies (�). [Perh. from the color of a yellow species. AS. buter-flēge, buttor-fleóge; cf. G. butterfliege, D. botervlieg. See Butter, and Fly.] (Zoöl.) A general name for the numerous species of diurnal Lepidoptera. [See Illust. under Aphrodite.]
Asclepias butterfly. See under Asclepias. — Butterfly fish(Zoöl.), the ocellated blenny (Blennius ocellaris) of Europe. See Blenny. The term is also applied to the flying gurnard. — Butterfly shell(Zoöl.), a shell of the genus Voluta. — Butterfly valve(Mech.), a kind of double clack valve, consisting of two semicircular clappers or wings hinged to a cross rib in the pump bucket. When open it somewhat resembles a butterfly in shape.