Longman Dictionary of Contemporary English
The Collaborative International Dictionary
lightbulb \lightbulb\, light bulb \light bulb\n. 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.
Syn: light bulb, bulb, incandescent lamp, electric light, electric-light bulb.
Douglas Harper's Etymology Dictionary
Wiktionary
n. 1 An evacuated glass bulb containing a metal filament which is heated by electrical resistance to produce light. 2 (context by extension English) An article that resembles such a bulb and converts electricity to light by any process. 3 (context figuratively English) (non-gloss definition Used in reference to the sudden arrival of a realization, an inspiration, an idea, or the like. English)
WordNet
n. electric lamp consisting of a glass bulb containing a wire filament (usually tungsten) that emits light when heated [syn: lightbulb, bulb, incandescent lamp, electric light, electric-light bulb]
Usage examples of "light bulb".
The artificial lighting at work might be a problem, but he'd brought along a grow light bulb, just in case.
The empty hallway was lit by a single naked light bulb, hanging forlornly from the low ceiling.
Lightlow continued pacing, nodding encouragingly as each students thought balloon became a light bulb.
It added light, a warm glow that the single light bulb under its conical shade could not hope to match.
About ten thousand to build the Doomsday Device and one to write the report saying that Project Light Bulb is an enormous success and requires further funding.
To make sure there was a little more resistance than air to prevent their touching, Mackensen lodged the light bulb between the open jaws, fixing it in place with a generous blob of glue.
The room was growing lighter, but not from the suspended electric light bulb above them.
She opened her eyes and looked straight into the hanging light bulb.
Then he pattered into the kitchen in his bare feet to look for another light bulb.