rec room vs game room

rec room and game room both are nouns.

Word	Noun	Adjective	Verb	Adverb
rec room	Yes	No	No	No
game room	Yes	No	No	No

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

rec room: a room equipped for informal entertaining
game room: a recreation room for noisy activities (parties or children's play etc)

Other hyponyms of rec room include canteen, family room, playroom, rumpus room.

rec room (noun)	game room (noun)
a room equipped for informal entertaining	a recreation room for noisy activities (parties or children's play etc)