Thessalonica vs urban center

Thessalonica and urban center both are nouns.

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

Thessalonica (noun)	urban center (noun)
a port city in northeastern Greece on an inlet of the Aegean Sea; second largest city of Greece	a large and densely populated urban area; may include several independent administrative districts