urban center vs Kirkuk

urban center and Kirkuk both are nouns.

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

urban center (noun)	Kirkuk (noun)
a large and densely populated urban area; may include several independent administrative districts	a city in northeastern Iraq; the center of a rich oilfield with pipelines to the Mediterranean