fringe vs city district

fringe and city district both are nouns.

Word	Noun	Adjective	Verb	Adverb
fringe	Yes	No	Yes	No
city district	Yes	No	No	No

As nouns, city district is a hypernym of fringe; that is, city district is a word with a broader meaning than fringe:

fringe (noun)	city district (noun)
an ornamental border consisting of short lengths of hanging threads or tassels	a district of a town or city
a border of hair that is cut short and hangs across the forehead
a social group holding marginal or extreme views
a part of the city far removed from the center
one of the light or dark bands produced by the interference and diffraction of light
the outside boundary or surface of something

fringe (verb)	city district (verb)
decorate with or as if with a surrounding fringe
adorn with a fringe