urban center vs Oporto

urban center and Oporto both are nouns.

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

urban center (noun)	Oporto (noun)
a large and densely populated urban area; may include several independent administrative districts	port city in northwest Portugal; noted for port wine