Newcastle vs city

Newcastle and city both are nouns.

Word	Noun	Adjective	Verb	Adverb
Newcastle	Yes	No	No	No
city	Yes	No	No	No

Newcastle (noun)	city (noun)
a port city in northeastern England on the River Tyne; a center for coal exports (giving rise to the expression `carry coals to Newcastle' meaning to do something unnecessary)	people living in a large densely populated municipality
	a large and densely populated urban area; may include several independent administrative districts
	an incorporated administrative district established by state charter