What is the difference between MC and DJ?

MC is short for 'Master of Ceremonies.' DJ is short for 'Disc Jockey.'

An MC is responsible for introducing acts and maintaining the agenda for a show, meeting or other event.

A DJ is responsible for playing recorded music. A DJ will often mix songs in a creative manner.

In short, an MC uses a microphone and a DJ uses turntables (or other recorded music devices.)