rotunda vs building

rotunda and building both are nouns.

Word	Noun	Adjective	Verb	Adverb
rotunda	Yes	No	No	No
building	Yes	No	No	No

As nouns, building is a hypernym of rotunda; that is, building is a word with a broader meaning than rotunda:

rotunda: a building having a circular plan and a dome
building: a structure that has a roof and walls and stands more or less permanently in one place

Other hypernyms of rotunda include edifice.

rotunda (noun)	building (noun)
a large circular room	the act of constructing something
a building having a circular plan and a dome	the commercial activity involved in repairing old structures or constructing new ones
	a structure that has a roof and walls and stands more or less permanently in one place
	the occupants of a building