urban center vs Bologna

urban center and Bologna both are nouns.

Word	Noun	Adjective	Verb	Adverb
urban center	Yes	No	No	No
Bologna	Yes	No	No	No

urban center (noun)	Bologna (noun)
a large and densely populated urban area; may include several independent administrative districts	the capital of Emilia-Romagna; located in northern Italy to the east of the Apennines