Other forms: lightbulbs
A lightbulb is the glass globe that glows when you flip the switch. Screwed or bayoneted into a fitting.
The old incandescent kind worked by heating a wire until it glowed and wasted most of its energy as heat, which is why they were phased out. LEDs use a fraction of the power and last for years. British fittings mostly use a bayonet cap and most of the world uses a screw thread. The lightbulb moment is the standard image for a sudden idea, complete with the drawing above the head.
1nounlightbulbA glass bulb producing light from electricity.
“The lightbulb on the landing has gone again.”
Also accepted in games: bulb, light bulb
yue - 電燈泡, as though the third person is a light bulb in the background.
Etymology from Wiktionary, CC BY-SA