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light bulb

American

noun

an electric light.

light bulb British

noun

Sometimes shortened to: bulb. a glass bulb containing a gas, such as argon or nitrogen, at low pressure and enclosing a thin metal filament that emits light when an electric current is passed through it

"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

Etymology

Origin of light bulb

First recorded in 1880–85

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Blog comment sections were notoriously dynamic, full of debate and discussion and lots of light bulb moments for writers and readers alike.

From Slate • Mar. 31, 2026

"The filters would be very good insulation, and someone had a light bulb moment and probably bought this as scrap off their manager," he said.

From BBC • Mar. 25, 2026

From that light bulb moment, Recondition, which Brown said created every piece with accessibility and style in mind, was born.

From BBC • Mar. 24, 2026

His most recent apartment inspection failed because the light bulb in the fridge was out.

From Slate • Oct. 8, 2025

An unadorned light bulb dangled down over several long wooden tables piled high with rags.

From "The Devil's Arithmetic" by Jane Yolen

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023