refectory vs dining-hall

refectory and dining-hall both are nouns.

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

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

refectory: a communal dining-hall (usually in a monastery)
dining-hall: a large room at a college or university; used especially for dining

refectory (noun)	dining-hall (noun)
a communal dining-hall (usually in a monastery)	a large room at a college or university; used especially for dining