Barcelona vs urban center

Barcelona and urban center both are nouns.

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

Barcelona (noun)	urban center (noun)
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	a large and densely populated urban area; may include several independent administrative districts