aunt vs great-aunt

aunt and great-aunt both are nouns.

Word	Noun	Adjective	Verb	Adverb
aunt	Yes	No	No	No
great-aunt	Yes	No	No	No

As nouns, great-aunt is a hyponym of aunt; that is, great-aunt is a word with a more specific, narrower meaning than aunt:

Other hyponyms of aunt include grandaunt, maiden aunt.

aunt (noun)	great-aunt (noun)
the sister of your father or mother; the wife of your uncle	an aunt of your father or mother