standing room vs room

standing room and room both are nouns.

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

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

Other hypernyms of standing room include elbow room, way.

standing room (noun)	room (noun)
room for passengers or spectators to stand	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

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