city limit vs city limits

city limit and city limits both are nouns.

Word	Noun	Adjective	Verb	Adverb
city limit	Yes	No	No	No
city limits	Yes	No	No	No

As nouns, city limit and city limits are synonyms defined as:

city limit and city limits: the limits of the area occupied by a city or town

city limit (noun)	city limits (noun)
the limits of the area occupied by a city or town	the limits of the area occupied by a city or town