academic gown vs robe

academic gown and robe both are nouns.

Word	Noun	Adjective	Verb	Adverb
academic gown	Yes	No	No	No
robe	Yes	No	Yes	No

As nouns, robe is a hypernym of academic gown; that is, robe is a word with a broader meaning than academic gown:

academic gown: a gown worn by academics or judges
robe: outerwear consisting of a long flowing garment used for official or ceremonial occasions

Other hypernyms of academic gown include gown.

academic gown (noun)	robe (noun)
a gown worn by academics or judges	any loose flowing garment
	outerwear consisting of a long flowing garment used for official or ceremonial occasions

academic gown (verb)	robe (verb)
	clothe formally; especially in ecclesiastical robes
	cover as if with clothing