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

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

Philips Hue has used IFA 2025 to bombard smart home fans with new product lines, cheaper light bulbs, and upgrades to some of its aging products. —PC Magazine, 4 Sep. 2025

For many children, this is a light bulb moment. —Suzanne Wright, USA Today, 3 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