Billings vs urban center

Billings and urban center both are nouns.

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

Billings (noun)	urban center (noun)
the largest city in Montana; located in southern Montana on the Yellowstone river	a large and densely populated urban area; may include several independent administrative districts