city vs Tianjin

city and Tianjin both are nouns.

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

city (noun)	Tianjin (noun)
people living in a large densely populated municipality	a major industrial center in northeastern China on the Grand Canal near the Yellow Sea; 3rd largest city in China
a large and densely populated urban area; may include several independent administrative districts
an incorporated administrative district established by state charter