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

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

The idea of an electric light bulb illuminating a room would be mesmerizing for many Americans at the time, but for Benjamin and first lady Caroline Harrison, bringing electricity into their home left them scared. —Paloma Chavez, PEOPLE, 29 Jan. 2026

Founded in the gold rush era, the company built glass for Edison's light bulbs in the late 1870s, and over the following decades moved into Pyrex cookware, car filters, spacecraft windows, TV screens and vials for Covid vaccines. —Katie Tarasov, CNBC, 27 Jan. 2026

Led by James Tour, PhD, a chemistry and materials science and nanoengineering professor at Rice University, the study aimed to reconstruct Edison’s original light bulb experiments using modern analytical tools. —Georgina Jedikovska, Interesting Engineering, 26 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