Motown vs metropolis

Motown and metropolis both are nouns.

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

Motown (noun)	metropolis (noun)
the largest city in Michigan and a major Great Lakes port; center of the United States automobile industry; located in southeastern Michigan on the Detroit river across from Windsor	people living in a large densely populated municipality
	a large and densely populated urban area; may include several independent administrative districts