speed limit vs ordinance

speed limit and ordinance both are nouns.

Word	Noun	Adjective	Verb	Adverb
speed limit	Yes	No	No	No
ordinance	Yes	No	No	No

As nouns, ordinance is a hypernym of speed limit; that is, ordinance is a word with a broader meaning than speed limit:

speed limit: regulation establishing the top speed permitted on a given road
ordinance: an authoritative command

Other hypernyms of speed limit include regulation.

speed limit (noun)	ordinance (noun)
regulation establishing the top speed permitted on a given road	the act of ordaining; the act of conferring (or receiving) holy orders
	an authoritative command
	a statute enacted by a city government