Mashhad vs urban center

Mashhad and urban center both are nouns.

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

Mashhad (noun)	urban center (noun)
the holy city of Shiite Muslims; located in northeastern Iran	a large and densely populated urban area; may include several independent administrative districts