dining room vs room

dining room and room both are nouns.

Word	Noun	Adjective	Verb	Adverb
dining room	Yes	No	No	No
room	Yes	No	Yes	No

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

dining room (noun)	room (noun)
a room used for dining	an area within a building enclosed by walls and floor and ceiling
	the people who are present in a room
	space for movement
	opportunity for

dining room (verb)	room (verb)
	live and take one's meals at or in