wash room vs bathroom

wash room and bathroom both are nouns.

Word	Noun	Adjective	Verb	Adverb
wash room	Yes	No	No	No
bathroom	Yes	No	No	No

As nouns, bathroom is a hypernym of wash room; that is, bathroom is a word with a broader meaning than wash room:

Other hypernyms of wash room include facility, can, john, lav, lavatory, privy, toilet.

wash room (noun)	bathroom (noun)
a toilet that is available to the public	a room (as in a residence) containing a bathtub or shower and usually a washbasin and toilet
	a room or building equipped with one or more toilets