Vladivostok vs urban center

Vladivostok and urban center both are nouns.

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

Vladivostok (noun)	urban center (noun)
a seaport in the Asian part of Russia	a large and densely populated urban area; may include several independent administrative districts