Volgograd vs urban center

Volgograd and urban center both are nouns.

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

Volgograd (noun)	urban center (noun)
a city in the European part of Russia on the Volga; site of German defeat in World War II in the winter of 1942-43	a large and densely populated urban area; may include several independent administrative districts