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

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

Ewing adds that even though LED bulbs use less energy than your granny’s light bulbs once did, LEDs still require energy to function. —Nafeesah Allen, Better Homes & Gardens, 2 Sep. 2025

The restoration of these lanterns involved replacing the original light bulbs with LED lights for sustainability reasons. —Isabelle Kliger, Forbes.com, 2 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