urban center vs Nizhni Novgorod

urban center and Nizhni Novgorod both are nouns.

Word	Noun	Adjective	Verb	Adverb
urban center	Yes	No	No	No
Nizhni Novgorod	Yes	No	No	No

urban center (noun)	Nizhni Novgorod (noun)
a large and densely populated urban area; may include several independent administrative districts	an industrial city in the European part of Russia; birthplace of Maksim Gorky