FM may refer to any of the following:
1. Short for frequency modulation, FM encoding is a method of recording data to a floppy disk or hard drive platter. This method of encoding is no longer used today and has been replaced with MFM.
2. When referring to the radio or an audio signal, FM is short for frequency modulation invented by Edwin Armstrong in 1933. FM is a method of transmitting a signal of greater quality at ranges of 80 MHz to 108 MHz at a shorter distance when compared to AM.