What does "lightbulb" mean?

Alternative spelling of light bulb.

Lightbulb

Common synonyms include: bulb, electric light, electric-light bulb, gooseberry, gooseberry, incandescent lamp.

noun, slang

noun, slang ·2 syllables ·Moderate ·College level

Noun

1
Alternative spelling of light bulb. alt-of, alternative
"A young orangutan in the San Diego Zoo became famous for unbolting the screening of his crib, removing the wires, and moving through the zoo nursery, unscrewing lightbulbs."
2
An uninvited third person joining a couple's date who prevents or hinders romantic interactions. Singapore, colloquial
"You two go ahead lah, I don't want to be lightbulb."
3
electric lamp consisting of a transparent or translucent glass housing containing a wire filament (usually tungsten) that emits light when heated by electricity wordnet

"Thomas Edison invented the electric lightbulb."

Calque from Cantonese 電燈泡／电灯泡 (din6 dang1 paau1), as though the third person is a light bulb in the background.

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.