Synonyms:
dimmer
Meaning: a rheostat that varies the current through an electric light in order to control the level of illumination
Usage examples
My eyesight's getting dimmer every day, I think.
It looked like the moon when it rises from behind clouds, and glows red and lurid from the horizon; and so this glowed, but not with the steady light of the moon, for the light was fitful, and sometimes flashed into a baleful brightness, which soon subsided into a dimmer lustre.