Newcastle vs urban center

Newcastle and urban center both are nouns.

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

Newcastle (noun)	urban center (noun)
a port city in northeastern England on the River Tyne; a center for coal exports (giving rise to the expression `carry coals to Newcastle' meaning to do something unnecessary)	a large and densely populated urban area; may include several independent administrative districts