- wing nut, wing-nut - any tree of the genus Pterocarya; fruit is a small winged nutlet; Caucasus to southeastern Asia
--1 is a kind of nut tree
--1 is a member of Pterocarya, genus Pterocarya
--1 has particulars: Caucasian walnut, Pterocarya fraxinifolia - wing nut, wing-nut, wing screw, butterfly nut, thumbnut - a threaded nut with winglike projections for thumb and forefinger leverage in turning
--2 is a kind of nut