What does "black light" mean?

A light bulb that emits ultraviolet light, usually used to create the illusion that anything white is glowing.

What is a synonym for "black light"?

Common synonyms include: ultraviolet light.

noun, slang

noun, slang ·Uncommon ·College level

Noun

1
A light bulb that emits ultraviolet light, usually used to create the illusion that anything white is glowing. countable
"Blacklights and a mirrored disco ball Every night's another reason why I left it all"
2
Ultraviolet radiation or light. slang, uncountable

"Blacklights and a mirrored disco ball Every night's another reason why I left it all"

From black + light, since ultraviolet light is invisible to the human eye.