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

This was the company that Thomas Edison built, with a management system so potent that investors once believed it could be applied to light bulbs, nuclear reactors, Saturday Night Live and its opaque GE Capital finance arm with equal results. —Diane Brady, Fortune, 6 Jan. 2026

Scenes from Thomas Edison's light bulb, the Empire State Building, the Model T Ford, and the Industrial Revolution, to name a few, are projected onto the Washington Monument. —Marvin Hurst, CBS News, 6 Jan. 2026

The Shiloh lamp is also compatible with dimmable light bulbs for a more customizable glow. —Kate McGregor, Architectural Digest, 6 Jan. 2026

Take care not to place sensitive species too close to grow light bulbs. —Lauren Landers, Better Homes & Gardens, 5 Jan. 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