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

The em dash, a punctuation mark a bit longer than a hyphen that denotes a long pause, has become the black light on the hotel sheets for AI-shamers—a sign that an essay, a letter or any kind of written work was written by a machine and not by a human.

From The Wall Street Journal

“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

This includes an incomplete copy of a typed manuscript titled "Black Light", which Brady appears to have written.

From BBC

Keightley writes in his own book that Brady told him "Black Light" was at least 600 pages long.

From BBC

The Bennett family's lawyer asked the documentary-makers to let the police know about "Black Light".

From BBC