light bulb

noun

variants or lightbulb

ˈlīt-ˌbəlb 

plural light bulbs or lightbulbs

: an electric lamp: such as

a

: one in which a filament gives off light when heated to incandescence by an electric current

called also incandescent, incandescent lamp

b

: one having a coating of fluorescent material on its inner surface that emits visible light : fluorescent lamp

especially : compact fluorescent light

c

: one using LEDs to generate light

Illustration of light bulb

• 1 bulb containing gas
• 2 filament
• 3 connecting and supporting wires
• 4 exhaust tube
• 5 screw base
• 6 base contact

Examples of light bulb in a Sentence

Recent Examples on the Web

The Shiloh lamp is also compatible with dimmable light bulbs for a more customizable glow. —Kate McGregor, Architectural Digest, 20 June 2025

The light bulb moment for Fleck was when both her professional and personal experiences showed her what validation can do. —Bruce Y. Lee, Forbes.com, 26 May 2025

Switching from incandescent to LED light bulbs saves an average household more than $200/year. —Rob Lewallen, San Diego Union-Tribune, 1 Apr. 2025

The 50-foot string has 25 shatterproof globe light bulbs that are spaced 2 feet apart. —Maggie Horton, People.com, 10 June 2025

Word History

First Known Use

1885, in the meaning defined above

Rhymes for light bulb

• lightbulb

Kids Definition

lightbulb

noun

light·​bulb ˈlīt-ˌbəlb 

: an electric lamp: as

a

: one in which a filament gives off light when heated by an electric current

called also incandescent lamp

b

: fluorescent lamp