Plovdiv vs urban center

Plovdiv and urban center both are nouns.

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

Plovdiv (noun)	urban center (noun)
an ancient city in southern Bulgaria; commercial center of an agricultural region	a large and densely populated urban area; may include several independent administrative districts