urban center vs Rotterdam

urban center and Rotterdam both are nouns.

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

urban center (noun)	Rotterdam (noun)
a large and densely populated urban area; may include several independent administrative districts	the 2nd largest city in the Netherlands; located in the western Netherlands near the North Sea