metropolis vs Arlington

metropolis and Arlington both are nouns.

Word	Noun	Adjective	Verb	Adverb
metropolis	Yes	No	No	No
Arlington	Yes	No	No	No

metropolis (noun)	Arlington (noun)
people living in a large densely populated municipality	a city in northern Texas between Dallas and Fort Worth
a large and densely populated urban area; may include several independent administrative districts