Definition of oak fly in English:
oak fly
noun
1Either of two long-legged orange and brown dipteran flies of the genus Rhagio (formerly Leptis; family Rhagionidae), R. lineola and especially the larger R. scolopacea.
2Fishing
An artificial fly imitating either of these.
Origin
Mid 17th century; earliest use found in Thomas Barker (fl. 1651), writer on angling.
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