Definitions for hairstreakˈhɛərˌstrik
Random House Webster's College Dictionary
any small, dark butterfly of the family Lycaenidae, having hairlike tails on the hind wings.
Origin of hairstreak:
hairstreak, hairstreak butterfly(noun)
small butterflies having striped markings under the wings
Any of many butterflies, of the subfamily Theclinae, that have hairlike projections on the back wings.
a butterfly of the genus Thecla; as, the green hairstreak (T. rubi)