city vs Port Arthur

city and Port Arthur both are nouns.

Word	Noun	Adjective	Verb	Adverb
city	Yes	No	No	No
Port Arthur	Yes	No	No	No

city (noun)	Port Arthur (noun)
people living in a large densely populated municipality	a battle in the Chino-Japanese War (1894); Japanese captured the port and fortifications from the Chinese
a large and densely populated urban area; may include several independent administrative districts	a major port city in northeastern China on the Liaodong Peninsula; now a part of Luda
an incorporated administrative district established by state charter