Definition of hairstreak
: any of a subfamily (Theclinae of the family Lycaenidae) of small butterflies usually having striped markings on the underside of the wings and thin filamentous projections from the hind wings
Recent Examples of hairstreak from the Web
The Fulvous hairstreak, another brown butterfly that feeds on Brazilian pepper, is now showing up north of Melbourne.
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First Known Use of hairstreak
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