cupola vs dome

cupola and dome both are nouns.

Word	Noun	Adjective	Verb	Adverb
cupola	Yes	No	No	No
dome	Yes	No	No	No

As nouns, dome is a hypernym of cupola; that is, dome is a word with a broader meaning than cupola:

cupola (noun)	dome (noun)
a roof in the form of a dome	a hemispherical roof
a vertical cylindrical furnace for melting iron for casting	a stadium that has a roof
	informal terms for a human head
	a concave shape whose distinguishing characteristic is that the concavity faces downward