Source : Free On-Line Dictionary of Computing

light-emitting diode
     
         (LED) a type of {diode} that emits light when
        current passes through it.  Depending on the material used the
        colour can be visible or infrared.  LEDs have many uses,
        visible LEDs are used as indicator lights on all sorts of
        electronic devices and in moving-message panels, while
        infrared LEDs are the heart of remote control devices.
     
        See also {smoke-emitting diode}.
     
        (1996-01-05)