butterfly nut vs wing-nut

butterfly nut and wing-nut both are nouns.

Word	Noun	Adjective	Verb	Adverb
butterfly nut	Yes	No	No	No
wing-nut	Yes	No	No	No

As nouns, butterfly nut and wing-nut are synonyms defined as:

butterfly nut and wing-nut: a threaded nut with winglike projections for thumb and forefinger leverage in turning

Other synonyms of butterfly nut include thumbnut, wing nut, wing screw.

butterfly nut (noun)	wing-nut (noun)
a threaded nut with winglike projections for thumb and forefinger leverage in turning	a threaded nut with winglike projections for thumb and forefinger leverage in turning
	any tree of the genus Pterocarya; fruit is a small winged nutlet; Caucasus to southeastern Asia