blue light

American  

[bloo lahyt] / ˈblu ˈlaɪt /

noun

1. 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.

2. 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.

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Etymology

Origin of blue light

First recorded in 1810–15

Example Sentences

See Examples For:

blue light

Simply shining blue light onto the mice triggered the same scratching behavior seen during mechanical stimulation, providing strong evidence that these neurons directly produce the itch sensation.

From Science Daily ● Jul. 14, 2026

Young said she noticed it when the Ring camera’s blue light would turn on, signaling recording was happening, at times when she and her family members had not press record.

From Los Angeles Times ● Jun. 25, 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

Low-energy infrared photons do not have enough energy to activate electrons, while high-energy photons such as blue light lose their extra energy as heat.

From Science Daily ● Mar. 28, 2026

He beckons to her, and she walks down the hallway, the blue light at the end making her bare head glow.

From "Divergent" by Veronica Roth