triclinium vs dining-room

triclinium and dining-room both are nouns.

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

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

triclinium: a dining room (especially a dining room containing a dining table with couches along three sides)
dining-room: a room used for dining

Other hypernyms of triclinium include dining room.

triclinium (noun)	dining-room (noun)
a dining table with couches along three sides in ancient Rome	a room used for dining
a dining room (especially a dining room containing a dining table with couches along three sides)