Mc has 8 different meanings across 4 categories:
Noun · Phrase · Proper Noun · Prefix
one million periods per second
Initialism of master of ceremonies.
Abbreviation of megacycle.
Abbreviation of millicurie.
To emcee, to act as a master of ceremonies.
Initialism of Merry Christmas..
Initialism of Minecraft.
Alternative form of Mac (Irish patronymic surnames meaning "son of")