urban center vs Krakau

urban center and Krakau both are nouns.

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

urban center (noun)	Krakau (noun)
a large and densely populated urban area; may include several independent administrative districts	an industrial city in southern Poland on the Vistula