ultraviolet

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adjective ul·tra·vi·o·let \ˌəl-trə-ˈvī-(ə-)lət\

Definition of ultraviolet

1 : situated beyond the visible spectrum at its violet end —used of radiation having a wavelength shorter than wavelengths of visible light and longer than those of X-rays
2 : relating to, producing, or employing ultraviolet radiation

ultraviolet

noun

See ultraviolet defined for English-language learners

See ultraviolet defined for kids

Recent Examples of ultraviolet from the Web

There are 10 of them, including two that can detect ultraviolet light from the moon and stars.

— sarah kaplan, Washington Post, "This creature has 10 eyes, legs that chew and blood that saved your life", 4 July 2017
By August, the City Council must choose between spending up to $500 million and 12 years to build a filtration treatment system or about $105 million and five years on a facility that will treat water with ultraviolet light.

— jessica floum, OregonLive.com, "Portland must make a $500 million call on removing parasites from its water", 27 June 2017
A 2015 state report said most of the victims that were then known had reported high exposure to ultraviolet light, such as through sunburns or tanning beds, which has been associated with the disease.

— bruce henderson, charlotteobserver, "As studies of a rare eye cancer in a small town continue, the number of cases grows", 22 June 2017
That airglow arises when individual gas atoms—previously created when ultraviolet light blasted gas molecules apart—

— sid perkins, Science | AAAS, "‘Bright night’ glowing sky mystery solved", 21 June 2017
Ground-level ozone is formed when nitrogen dioxide and volatile organic compounds combine in the atmosphere and are cooked by ultraviolet radiation.

— james f. mccarty, cleveland.com, "Northeast Ohio air getting better, but don't breathe easy just yet", 19 June 2017
Experiments proved that ultraviolet light was germicidal.

— jeanne kisacky, Smithsonian, "When Fresh Air Went Out of Fashion at Hospitals", 14 June 2017
No matter where your complexion falls on the Fitzpatrick Skin Type scale, ultraviolet radiation (UV) from the sun or tanning beds will damage your skin.

— kerry hanson, Smithsonian, "How Sunscreen Protects Your Skin’s DNA", 31 May 2017
Bees, for example, use ultraviolet vision to find flowers that have also evolved ultraviolet markings.

— joshua sokol, The Atlantic, "Does a Spider Use Its Web Like You Use Your Smartphone?", 30 May 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'ultraviolet'. Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of ultraviolet

1840

ULTRAVIOLET Defined for English Language Learners

ultraviolet

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adjective

Definition of ultraviolet for English Language Learners

—used to describe rays of light that cannot be seen and that are slightly shorter than the rays of violet light

ULTRAVIOLET Defined for Kids

ultraviolet

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adjective ul·tra·vi·o·let \ˌəl-trə-ˈvī-ə-lət\

Definition of ultraviolet for Students

: relating to, producing, or being energy that is like light but has a slightly shorter wavelength and lies beyond the violet end of the spectrum

Medical Dictionary

ultraviolet

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adjective ul·tra·vi·o·let \ˌəl-trə-ˈvī-(ə-)lət\

Medical Definition of ultraviolet

1: situated beyond the visible spectrum at its violet end—used of radiation having a wavelength shorter than wavelengths of visible light and longer than those of X-rays
2: relating to, producing, or employing ultraviolet radiation