megacycle per second vs Mc

megacycle per second and Mc both are nouns.

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

As nouns, megacycle per second and Mc are synonyms defined as:

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

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