dining-hall vs dining-room

dining-hall and dining-room both are nouns.

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

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

dining-hall: a large room at a college or university; used especially for dining
dining-room: a room used for dining

Other hypernyms of dining-hall include dining room.

dining-hall (noun)	dining-room (noun)
a large room at a college or university; used especially for dining	a room used for dining