A MIDI file is a file format that stores music data. It stands for Musical Instrument Digital Interface and it's a way for electronic instruments and computers to communicate musical information. A MIDI file contains information about which notes were played, when they were played, and how long they were played for, but it does not contain any audio data. Instead, it must be played back through a device that can interpret the MIDI data and generate sound. MIDI files are often used for creating and editing music, and for controlling music equipment such as synthesizers and drum machines.