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

Titans of Innovation Roundtable Billy Parks, head of FOX creator studios, had a light bulb moment 15 years ago while working with AT&T. — Mya Copeland, Variety, 18 Sep. 2026

Here on the southern edge of Indonesia, the stars glow like light bulbs, even on the horizon. — Michelle Jana Chan, Condé Nast Traveler, 14 Sep. 2026

Choose bedside reading light bulbs of warm white, deep amber or red that have low or near-zero effective color temperatures. — Sandee Lamotte, CNN Money, 9 Sep. 2026

Part of a continuing cycle People often think of scientific discovery as a eureka light bulb above the head of a brilliant scientist, but discovery rarely happens that way. — Don Figer, The Conversation, 27 Aug. 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