urban center vs Patrai

urban center and Patrai both are nouns.

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

urban center (noun)	Patrai (noun)
a large and densely populated urban area; may include several independent administrative districts	a port city in western Greece in the northwestern Peloponnese on an inlet of the Ionian Sea; was a major trade center from the 5th century BC to the 3rd century BC; commercial importance revived during the Middle Ages