megahertz vs megacycle

megahertz and megacycle both are nouns.

Word	Noun	Adjective	Verb	Adverb
megahertz	Yes	No	No	No
megacycle	Yes	No	No	No

As nouns, megahertz and megacycle are synonyms defined as:

Other synonyms of megahertz include Mc, megacycle per second, MHz.

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