MIDI stands for Musical Instrument Digital Interface and is a communication and data storage protocol developed in the 1980’s by a consortium of manufactures to specify how their devices could all work with each other.
In other words, MIDI is not a type of sound or sound producing means. Instead, MIDI is a standardized way of sending data between two places. Originally, this allows a single music instrument controller, such as a standard piano keyboard, to send MIDI data to a synthesizer, which would then use that data to determine how to make sound. This would allow a single player to use a single controller, to potentially play numerous MIDI-capable synthesizers, without the need for a specialized controller for each one.
As technology has progressed, MIDI has continued to evolve. As computers “took-off” someone suggested including a MIDI port on a computer, so that the computer could send data to the MIDI-capable synthesizer and control it. As the Digital Audio Workstation took hold, MIDI became a means of communicating within the DAW, so as to play digital synthesize instruments. MIDI was also specified as a file type, so that music data could be represented through a simple, and relatively small file (compared to an audio file).
To learn about MIDI, I am going to ask you to do a lot of reading this week. There is no need for me to re-write information that is better presented in other places.
In addition, please read the entire MIDI chapter form the Indiana University Introduction to Computer Music textbook.