ballroom vs disco

ballroom and disco both are nouns.

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

As nouns, disco is a hyponym of ballroom; that is, disco is a word with a more specific, narrower meaning than ballroom:

Other hyponyms of ballroom include discotheque.

ballroom (noun)	disco (noun)
large room used mainly for dancing	a public dance hall for dancing to recorded popular music
	popular dance music (especially in the late 1970s); melodic with a regular bass beat; intended mainly for dancing at discotheques

ballroom (verb)	disco (verb)
	dance to disco music