pixie vs fay

pixie and fay both are nouns.

Word	Noun	Adjective	Verb	Adverb
pixie	Yes	No	No	No
fay	Yes	No	No	No

As nouns, fay is a hypernym of pixie; that is, fay is a word with a broader meaning than pixie:

Other hypernyms of pixie include faerie, faery, fairy, sprite.

pixie (noun)	fay (noun)
(folklore) fairies that are somewhat mischievous	a small being, human in form, playful and having magical powers
creeping evergreen shrub having narrow overlapping leaves and early white star-shaped flowers; of the pine barrens of New Jersey and the Carolinas