What Is an MIDI?

C'mon, you don't know what an MIDI file is? It is a file that contains all the information about a song: instruments, notes, chords, drums, and so on. Your computer passes this information to your sound card, and plays the song. Because it is only the music, there is no words, because, how could a sound card know every popular singer's voice?! These files are very small, because they don't contain music, they contain instuctions on how to play music.
These files can be sent to MIDI-compatable Instruments via the PC, and played on the instrument...