blue light
Americannoun
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a band of the visible light spectrum that has a shorter wavelength and produces higher energy than other colors of light: occurring in sunlight and emitted by electronic devices that use LED technology.
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American History, Usually Disparaging. Also Blue Light a member of a faction of the American Federalist party considered disloyal for opposing the War of 1812: so called from the claim that they flashed blue light signals to alert the British to the presence of blockade runners.
Etymology
Origin of blue light
First recorded in 1810–15
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
These instruments search for brief flashes of blue light produced through a phenomenon called Cherenkov radiation.
From Science Daily ● Nov. 2, 2026
The BBC's Evan Davis, who was travelling through the Eurotunnel to Calais at the time of the incident, witnessed blue light vehicles "concentrated on one of the platforms" as he entered France.
From BBC ● Oct. 15, 2026
In 2020, Longcore co-published a study linking artificial night light, including blue light emitted by LEDs, to cancer.
From Los Angeles Times ● May 8, 2026
Depending on the situation, a Tesla will gently warn with a message and a flashing blue light on the center screen, buzz, or require pressure on the steering wheel.
From Barron's ● May 3, 2026
The dark blue light of dawn was starting to creep in through the laundry room window.
From "Ready Player One: A Novel" by Ernest Cline
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