dimmer switch

Noun

 * 1) A light switch which can adjust the brightness of the switched lamp from dim to bright, as well as turning it on and off.
 * 2)  A switch that changes the headlamps on a motor vehicle from low to high and from high to low beam; a high-beam switch; a brights switch.
 * 1)  A switch that changes the headlamps on a motor vehicle from low to high and from high to low beam; a high-beam switch; a brights switch.