rate of interest vs rate

rate of interest and rate both are nouns.

Word	Noun	Adjective	Verb	Adverb
rate of interest	Yes	No	No	No
rate	Yes	No	Yes	No

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

Other hypernyms of rate of interest include charge per unit.

rate of interest (noun)	rate (noun)
the percentage of a sum of money charged for its use	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

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