dining-room set vs dining room set

dining-room set and dining room set both are nouns.

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

As nouns, dining-room set and dining room set are synonyms defined as:

dining-room set and dining room set: a suite of furniture for the dining room

Other synonyms of dining-room set include dining-room suite, dining room suite.

dining-room set (noun)	dining room set (noun)
a suite of furniture for the dining room	a suite of furniture for the dining room