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

Everyone else was like a dim light bulb set against Usha’s radiance. —Clare Mulroy, USA Today, 10 May 2026

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, 26 Apr. 2026

Lighting Technology The type of light bulb in use dramatically affects whether turning off lights is necessary. —Nafeesah Allen, Better Homes & Gardens, 25 Apr. 2026

People obsessively worked on light bulbs and the systems that powered them, finding little improvements year after year. —Literary Hub, 8 Apr. 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