L.A. vs urban center

L.A. and urban center both are nouns.

Word	Noun	Adjective	Verb	Adverb
L.A.	Yes	No	No	No
urban center	Yes	No	No	No

L.A. (noun)	urban center (noun)
a city in southern California; motion picture capital of the world; most populous city of California and second largest in the United States	a large and densely populated urban area; may include several independent administrative districts