bath linen vs flannel

bath linen and flannel both are nouns.

Word	Noun	Adjective	Verb	Adverb
bath linen	Yes	No	No	No
flannel	Yes	No	No	No

As nouns, flannel is a hyponym of bath linen; that is, flannel is a word with a more specific, narrower meaning than bath linen:

bath linen: linens for use in the bathroom
flannel: bath linen consisting of a piece of cloth used to wash the face and body

Other hyponyms of bath linen include bath mat, bath towel, face cloth, washcloth, washrag.

bath linen (noun)	flannel (noun)
linens for use in the bathroom	a soft light woolen fabric; used for clothing
	bath linen consisting of a piece of cloth used to wash the face and body
	(usually in the plural) trousers made of flannel or gabardine or tweed or white cloth