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