old woman vs crone

old woman and crone both are nouns.

Word	Noun	Adjective	Verb	Adverb
old woman	Yes	No	No	No
crone	Yes	No	No	No

As nouns, crone is a hyponym of old woman; that is, crone is a word with a more specific, narrower meaning than old woman:

Other hyponyms of old woman include beldam, beldame, granny, beldam, beldame, hag, witch, mother.

old woman (noun)	crone (noun)
a woman who is old	an ugly evil-looking old woman
herb with greyish leaves found along the east coast of North America; used as an ornamental plant