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

There, a group of KPMG staffers followed and sometimes interjected their own thoughts on the building, while workers fastened the last screws on light bulbs and organized plants strewn around the office. —Eva Roytburg, Fortune, 5 Nov. 2025

Some organizations will accept new LED bulbs still in the package, but don't expect a thrift store to want your old light bulbs. —Brandee Gruener, Southern Living, 5 Nov. 2025

When people realized that the blue photons were firing at them not only from their devices but from every light bulb, there was a rush to avoid bright white LEDs altogether. —Rowan Jacobsen, Harpers Magazine, 24 Oct. 2025

The inventor of the light bulb is also credited with developing many other devices in mass communication, sound recording and motion pictures. —Arizona Republic, AZCentral.com, 18 Oct. 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