urban center vs Mobile

urban center and Mobile both are nouns.

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

urban center (noun)	Mobile (noun)
a large and densely populated urban area; may include several independent administrative districts	a port in southwestern Alabama on Mobile Bay
	a river in southwestern Alabama; flows into Mobile Bay