greenroom vs room

greenroom and room both are nouns.

Word	Noun	Adjective	Verb	Adverb
greenroom	Yes	No	No	No
room	Yes	No	Yes	No

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

greenroom: a backstage room in a theater where performers rest or have visitors
room: an area within a building enclosed by walls and floor and ceiling

greenroom (noun)	room (noun)
a backstage room in a theater where performers rest or have visitors	an area within a building enclosed by walls and floor and ceiling
	the people who are present in a room
	space for movement
	opportunity for

greenroom (verb)	room (verb)
	live and take one's meals at or in