1. a person or thing that dims.
  2. Also called dimmer switch. a rheostat or similar device by which the intensity of an electric light may be varied.
  3. dimmers,
    1. the low-beam headlights of an automobile or truck.
    2. the small, parking lights of an automobile.

Origin of dimmer

First recorded in 1815–25; dim + -er1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for dimmer-switch


  1. a device, such as a rheostat, for varying the current through an electric light and thus changing the illumination
  2. (often plural) US
    1. a dipped headlight on a road vehicle
    2. a parking light on a car
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for dimmer-switch



1822, agent noun from dim (v.). Of mechanisms for reducing the brightness of electric lights, from 1905.

Online Etymology Dictionary, © 2010 Douglas Harper