linen vs bath linen

linen and bath linen both are nouns.

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

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

Other hyponyms of linen include bed linen, doily, doyley, doyly, napery, table linen.

linen (noun)	bath linen (noun)
white goods or clothing made with linen cloth	linens for use in the bathroom
a fabric woven with fibers from the flax plant
a high-quality paper made of linen fibers or with a linen finish