But·ter·fly n.; pl. Butterflies Zool. A general name for the numerous species of diurnal Lepidoptera.
Note: [See Illust. under Aphrodite.]
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.