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

Across the 20th century, GE was a poster child for American industrial invention and scale, from power generators and light bulbs to jet engines, medical imaging, and early computing. —Kaif Shaikh, Interesting Engineering, 21 Jan. 2026

Household Glass Window panes, mirrors, light bulbs and tableware are impractical to recycle. —Chris Baskind, Treehugger, 20 Jan. 2026

That’s when the light bulb goes off. —Dave Quinn, PEOPLE, 20 Jan. 2026

Layer a doormat, add a winter-hardy plant or swap in warmer light bulbs. —Avery Newmark, AJC.com, 14 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