Officially, MIDI stands for Musical Instrument Digital Interface, and it was invented in 1982. These days, it refers to three components:
1. A physical connector between electronic instruments and between electronic instruments and a MIDI controller, usually a keyboard. The connector takes the form of MIDI IN and MIDI OUT jacks form which MIDI cables can bet plugged into any electronic instruments (and youd be surprised at how much music hardware out there today is MIDI-capable almost every detachable keyboard is!)
2. A message format this message format is the heart of MIDI. This format is made up not of the sounds themselves, but simply the commands that are issued by the MIDI keyboard to the electronic instruments telling them how to play a given song (play the violin turn down the volume to XX, adjust the pitch to YY, etc.)
With the above two components, a musician was able to control a string of musical instruments from a single keyboard, giving him a one-man band effect.
3. A storage format in other words, MIDI files. This latecomer of the MIDI trinity was what really did the trick because it allowed musicians to record their creations and...