dining room vs mess

dining room and mess both are nouns.

Word	Noun	Adjective	Verb	Adverb
dining room	Yes	No	No	No
mess	Yes	No	Yes	No

As nouns, mess is a hyponym of dining room; that is, mess is a word with a more specific, narrower meaning than dining room:

Other hyponyms of dining room include dining-hall, mess hall, triclinium.

dining room (noun)	mess (noun)
a room used for dining	a (large) military dining room where service personnel eat or relax
	a meal eaten in a mess hall by service personnel
	soft semiliquid food
	(often followed by `of') a large number or amount or extent
	a state of confusion and disorderliness
	informal terms for a difficult situation

dining room (verb)	mess (verb)
	make a mess of or create disorder in
	eat in a mess hall