Astrakhan vs urban center

Astrakhan and urban center both are nouns.

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

Astrakhan (noun)	urban center (noun)
a city in southwestern Russia on the delta of the Volga River	a large and densely populated urban area; may include several independent administrative districts