ballroom vs room

ballroom and room both are nouns.

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

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

ballroom (noun)	room (noun)
large room used mainly for dancing	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

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