speed vs rate

speed and rate both are nouns.

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

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

Other hypernyms of speed include pace.

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

speed (noun)	rate (noun)
changing location rapidly	the relative speed of progress or change
a central nervous system stimulant that increases energy and decreases appetite; used to treat narcolepsy and some forms of depression	amount of a charge or payment relative to some basis
a rate (usually rapid) at which something happens	a quantity or amount or measure considered as a proportion of another quantity or amount or measure
the ratio of the focal length to the diameter of a (camera) lens system	a magnitude or frequency relative to a time unit
distance travelled per unit time

speed (verb)	rate (verb)
move faster	assign a rank or rating to
cause to move faster	estimate the value of
move very fast	be worthy of or have a certain rating
travel at an excessive or illegal velocity
move hurridly