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

One of his two wins came in the Pennsylvania Derby last year and his fans thought the light bulb had come on for good. — Danny Brewer, Forbes.com, 25 June 2026

No more waiting for the light bulb to turn on. — Dieter Kurtenbach, Mercury News, 24 June 2026

By the second day of braiding, a light bulb went off in her engineer's brain. — Annie Blay-Tettey, Allure, 23 June 2026

Remarkably, the brain performs all of these tasks while consuming only about 20 watts of power—less electricity than many household light bulbs. — Encyclopedia Britannica, 17 June 2026

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