ultraviolet

American  

[uhl-truh-vahy-uh-lit] / ˌʌl trəˈvaɪ ə lɪt /

adjective

1. beyond the violet in the spectrum, corresponding to light having wavelengths shorter than 4000 angstrom units.

2. pertaining to, producing, or utilizing light having such wavelengths.

   an ultraviolet lamp.

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noun

1. ultraviolet radiation.

ultraviolet British  

/ ˌʌltrəˈvaɪəlɪt /

noun

1. the part of the electromagnetic spectrum with wavelengths shorter than light but longer than X-rays; in the range 0.4 × 10 ^–6 and 1 × 10 ^–8 metres

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adjective

1.  UV.  of, relating to, or consisting of radiation lying in the ultraviolet

   ultraviolet radiation

ultraviolet Scientific  

/ ŭl′trə-vī′ə-lĭt /

1. Relating to electromagnetic radiation having frequencies higher than those of visible light but lower than those of x-rays, approximately 10 ¹⁵ –10 ¹⁶ hertz. Some animals, such as bees, are capable of seeing ultraviolet radiation invisible to the human eye.

2. See more at electromagnetic spectrum

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1. Ultraviolet light or the ultraviolet part of the spectrum.

2. See Note at infrared

Etymology

Origin of ultraviolet

First recorded in 1870–75; ultra- + violet

Compare meaning

How does ultraviolet compare to similar and commonly confused words? Explore the most common comparisons:

• infrared vs. ultraviolet

Explanation

Use the adjective ultraviolet to describe light with a wavelength that's less than visible light, but longer than x-rays. You can't see ultraviolet light. You might hear people talk about ultraviolet light as UV radiation — it's the part of sunlight that can give you a sunburn if you're exposed to it for too long. In physics, this kind of electromagnetic radiation is defined by how long its waves are. The word itself, ultraviolet, refers to the fact that its wavelength is shorter than the violet end of the spectrum of visible light. The Latin prefix ultra means "beyond."

Example Sentences

The analysts expect revenue from ASML’s extreme ultraviolet lithography machines to grow 37% in 2027 and 10% in 2028, above prior forecasts of 26% growth in 2027 and a 1% decline in 2028.

From The Wall Street Journal • May 20, 2026

The pyrimidone structure resembles a component found naturally in DNA that can reversibly change shape when exposed to ultraviolet light.

From Science Daily • May 15, 2026

Lasers and radio are both invisible electromagnetic waves but lasers, usually ultraviolet light, offer cost, security and space-saving advantages.

From The Wall Street Journal • May 12, 2026

The particles then traveled through three diffraction gratings generated by ultraviolet laser beams.

From Science Daily • May 11, 2026

Beyond the ultraviolet is the X-ray part of the spectrum, and beyond the X- rays are the gamma rays.

From "Cosmos" by Carl Sagan