megacycle vs Mc

megacycle and Mc both are nouns.

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

As nouns, megacycle and Mc are synonyms defined as:

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

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