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

Dramatic lighting and vaulted wood ceilings studded with gold dipped light bulbs lead you into the basement of the historic hotel. —Nathanael Gassett, Bon Appetit Magazine, 23 Sep. 2025

For example, someone offers you a step stool and hands you the light bulb. —Melanie Draheim, Forbes.com, 18 Sep. 2025

Mimicking the human brain Human brains are known for performing billions of computations while using about the same energy as a single light bulb. —Atharva Gosavi, Interesting Engineering, 17 Sep. 2025

Get a light cover to soften any overhead lights, or swap out your usual light bulbs for some that produce a warmer glow. —Andrea Beck, Better Homes & Gardens, 10 Sep. 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