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

These Philips smart light bulbs also react to voice commands via Alexa or Google Assistant. —Yelena Moroz Alpert, Architectural Digest, 6 Feb. 2026

Start small with easy, affordable tweaks like candles, soft light bulbs, or an arrangement of pretty blooms at the center of the table. —Kate Donovan, Martha Stewart, 5 Feb. 2026

There's a wonderful tradition in the theater where a single light bulb is left glowing when the stage is empty. —Danielle Parker, CBS News, 3 Feb. 2026

Make sure to choose the best dimmer switch that matches your needs, type of room, and type of light bulbs. —Lee Wallender, The Spruce, 31 Jan. 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