butterfly nut vs wing screw

butterfly nut and wing screw both are nouns.

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

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

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

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

butterfly nut (noun)	wing screw (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