cassock vs inner rason

cassock and inner rason both are nouns.

Word	Noun	Adjective	Verb	Adverb
cassock	Yes	No	No	No
inner rason	Yes	No	No	No

As nouns, inner rason is a hyponym of cassock; that is, inner rason is a word with a more specific, narrower meaning than cassock:

cassock: a black garment reaching down to the ankles; worn by priests or choristers
inner rason: a long, collared garment coming to the feet, with narrow, tapered sleeves, worn by all major and minor clergy, monastics, and often by male seminarians.

Other hyponyms of cassock include soutane, outer cassock, outer rason, inner cassock.

cassock (noun)	inner rason (noun)
a black garment reaching down to the ankles; worn by priests or choristers	a long, collared garment coming to the feet, with narrow, tapered sleeves, worn by all major and minor clergy, monastics, and often by male seminarians.