metropolis vs San Luis Potosi

metropolis and San Luis Potosi both are nouns.

Word	Noun	Adjective	Verb	Adverb
metropolis	Yes	No	No	No
San Luis Potosi	Yes	No	No	No

metropolis (noun)	San Luis Potosi (noun)
people living in a large densely populated municipality	a city in central Mexico, in the state San Luis Potosi
a large and densely populated urban area; may include several independent administrative districts