velocity vs rate

velocity and rate both are nouns.

Word	Noun	Adjective	Verb	Adverb
velocity	Yes	No	No	No
rate	Yes	No	Yes	No

As nouns, rate is a hypernym of velocity; that is, rate is a word with a broader meaning than velocity:

velocity (noun)	rate (noun)
distance travelled per unit time	the relative speed of progress or change
	amount of a charge or payment relative to some basis
	a quantity or amount or measure considered as a proportion of another quantity or amount or measure
	a magnitude or frequency relative to a time unit

velocity (verb)	rate (verb)
	assign a rank or rating to
	estimate the value of
	be worthy of or have a certain rating