D defs.my
Entry 1 sense Webster, 1913

lightbulb

· IPA /ˈlaɪtˌbʌlb/
01 n. A glass bulb with metallic contacts on the outside connected to a wire filament (usually tungsten) inside that emits light when heated by p…
  1. 1.
    A glass bulb with metallic contacts on the outside connected to a wire filament (usually tungsten) inside that emits light when heated by passage of electricity through the filament; -- used as the replaceable light-emitting component of an electric lamp, flashlight, lighting fixture, etc.