urban center vs Barcelona

urban center and Barcelona both are nouns.

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

urban center (noun)	Barcelona (noun)
a large and densely populated urban area; may include several independent administrative districts	a city in northeastern Spain on the Mediterranean; 2nd largest Spanish city and the largest port and commercial center; has been a center for radical political beliefs