megacycle per second vs rate

megacycle per second and rate both are nouns.

Word	Noun	Adjective	Verb	Adverb
megacycle per second	Yes	No	No	No
rate	Yes	No	Yes	No

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

megacycle per second (noun)	rate (noun)
one million periods per second	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

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