urban center vs Sparta

urban center and Sparta both are nouns.

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

urban center (noun)	Sparta (noun)
a large and densely populated urban area; may include several independent administrative districts	an ancient Greek city famous for military prowess; the dominant city of the Peloponnesus prior to the 4th century BC