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

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

“I love watching the light bulb go off, watching them be inspired,” Gill said.

From Los Angeles Times • Oct. 27, 2025

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

From Slate • Oct. 8, 2025

Would you believe that for me right then it was like one of those comic books where the light bulb goes on over Mandrake the Magician’s head?

From "The Princess Bride" by William Goldman

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