Butterfly n. (pl. butterflies) (Zool.) A general name for the numerous species of diurnal Lepidoptera. Asclepias butterfly. See under Asclepias. Butterfly fish (Zool.), the ocellated blenny (Blennius ocellaris) of Europe. See Blenny. The term is also applied to the flying gurnard. Butterfly shell (Zool.), 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.
