urban center vs Ostrava

urban center and Ostrava both are nouns.

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

urban center (noun)	Ostrava (noun)
a large and densely populated urban area; may include several independent administrative districts	an industrial city in northwestern Czech Republic in the Moravian lowlands; located in the coal mining area of Silesia