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

In contrast, regulatory bodies like the FTC have been part of the federal government for longer than the light bulb.

From Slate • Dec. 11, 2025

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

From Los Angeles Times • Oct. 27, 2025

At home he shares one light bulb between the two rooms that make up the small house.

From BBC • Mar. 25, 2025

He was sitting under a bare light bulb at a wobbly card table.

From "Flush" by Carl Hiaasen

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