Ur vs urban center

Ur and urban center both are nouns.

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

Ur (noun)	urban center (noun)
an ancient city of Sumer located on a former channel of the Euphrates River	a large and densely populated urban area; may include several independent administrative districts