black light

American  

noun

1. invisible infrared or ultraviolet light.

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black light British  

noun

1. the invisible electromagnetic radiation in the ultraviolet and infrared regions of the spectrum

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black light Scientific  

1. Invisible ultraviolet radiation. Black light causes certain fluorescent materials to emit visible light.

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Etymology

Origin of black light

First recorded in 1925–30

Example Sentences

“It opened with a subway shot and when the screen went dark, she had a black light that showed up all the graffiti and I was like, ‘Who is this?

From Los Angeles Times • Nov. 19, 2025

When they shine a black light on the coral, organic compounds in the coral cause it to fluoresce.

From Science Daily • Mar. 18, 2024

The term “uranium glass” generally describes glass with uranium oxide, which glows under a black light.

From Washington Post • Oct. 11, 2022

Ms. Califf of the Arizona-Sonora Desert Museum said she had to travel to the desert to find more bark scorpions, which she hunts at night with a black light because they glow in the dark.

From New York Times • May 3, 2022

I walk into the closet, where the black light has been replaced by a regular old bulb.

From "All The Bright Places" by Jennifer Niven