urban center vs Greater Sudbury

urban center and Greater Sudbury both are nouns.

Word	Noun	Adjective	Verb	Adverb
urban center	Yes	No	No	No
Greater Sudbury	Yes	No	No	No

urban center (noun)	Greater Sudbury (noun)
a large and densely populated urban area; may include several independent administrative districts	a city in south central Canada in Ontario; a major nickel mining center