LED stands for light-emitting diode. These impressive little lights are found in tons of different applications and devices. They produce the numbers in your digital clock, transmit information from your remote control, light up your watch, and tell you when your toaster is on. Unlike ordinary incandescent bulbs which use a filament that can burn out, LEDs are illuminated by the movement of electrons in a semiconductor material.
LEDs generally cost more than incandescents or CFLs but they use less energy and last significantly longer.