city district vs fringe

city district and fringe both are nouns.

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

As nouns, fringe is a hyponym of city district; that is, fringe is a word with a more specific, narrower meaning than city district:

city district (noun)	fringe (noun)
a district of a town or city	an ornamental border consisting of short lengths of hanging threads or tassels
	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

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