outer garment vs aba

outer garment and aba both are nouns.

Word	Noun	Adjective	Verb	Adverb
outer garment	Yes	No	No	No
aba	Yes	No	No	No

As nouns, aba is a hyponym of outer garment; that is, aba is a word with a more specific, narrower meaning than outer garment:

Other hyponyms of outer garment include cloak, coat, frock, izar, snowsuit.

outer garment (noun)	aba (noun)
a garment worn over other garments	a fabric woven from goat hair and camel hair
	a loose sleeveless outer garment made from aba cloth; worn by Arabs