radiation

noun
ra·​di·​a·​tion | \ ˌrā-dē-ˈā-shən How to pronounce radiation (audio) \

Definition of radiation

1a : the action or process of radiating
b : the process of emitting radiant energy in the form of waves or particles
c(1) : the combined processes of emission, transmission, and absorption of radiant energy
(2) : the transfer of heat by radiation — compare conduction, convection
2a : something that is radiated
b : energy radiated in the form of waves or particles
3 : radial arrangement

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Other Words from radiation

radiational \ ˌrā-​dē-​ˈā-​shnəl How to pronounce radiational (audio) , -​shə-​nᵊl \ adjective
radiationless \ ˌrā-​dē-​ˈā-​shən-​ləs How to pronounce radiationless (audio) \ adjective
radiative \ ˈrā-​dē-​ˌā-​tiv How to pronounce radiative (audio) \ adjective

Examples of radiation in a Sentence

She was exposed to high levels of radiation. He goes in for radiation next week. the sun's radiation of heat
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Recent Examples on the Web

Many got stuck, broke down or had their circuits fried by the intense radiation. The Economist, "Cleaning up nuclear waste is an obvious task for robots," 20 June 2019 Hulk later theorizes that the stones expel gamma radiation, the same radiation that gave Bruce Banner his Hulk powers. Eliana Dockterman, Time, "What's Next for the X-Men After Dark Phoenix?," 7 June 2019 This sick longing for security is a dangerous thing, Meg, as insidious as the radiation from a nuclear explosion. Meghan Cox Gurdon, WSJ, "Children’s Books: Stirring Up Fresh Life Endlessly," 21 Dec. 2018 Bavarian space fans are proud of the NIRSpec, a near-infrared spectrometer that helps NASA’s James Webb Space Telescope detect the weakest radiation from galaxies. Sonja Peteranderl, The Verge, "Bavaria’s space program shot to viral fame — but it may be in trouble," 20 Oct. 2018 Earth's magnetic field protects the ISS from much of the radiation of space. Anchorage Daily News, "What the Space Age taught us: Earth is the best of all possible worlds," 23 June 2019 Atacama’s infrequent rains and the highest solar radiation in the world — 30 percent higher on average than in the Mojave Desert — result in fast evaporation and allow miners to produce high-quality lithium at a low cost. Washington Post, "The element is needed for rechargeable batteries, but there’s a cost for extracting it.," 12 June 2019 The powerful energy radiation found in deep space can cause those strands to break down. David Grossman, Popular Mechanics, "NASA Is Launching Yeast Into Deep Space," 21 May 2019 But given the harsh radiation prevalent throughout space, and the challenges of reproducing in low gravity, that’s easier said than done. Amber Jorgenson, Discover Magazine, "Sex and the Cosmic City," 18 Apr. 2019

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

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First Known Use of radiation

15th century, in the meaning defined at sense 1a

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Statistics for radiation

Last Updated

16 Jul 2019

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The first known use of radiation was in the 15th century

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More Definitions for radiation

radiation

noun

English Language Learners Definition of radiation

: a type of dangerous and powerful energy that is produced by radioactive substances and nuclear reactions
medical : the use of controlled amounts of radiation for the treatment of diseases (such as cancer)
: energy that comes from a source in the form of waves or rays you cannot see

radiation

noun
ra·​di·​a·​tion | \ ˌrā-dē-ˈā-shən How to pronounce radiation (audio) \

Kids Definition of radiation

1 : the process of giving off energy in the form of waves or particles
2 : something that is radiated (as light or X-rays)

radiation

noun
ra·​di·​a·​tion | \ ˌrād-ē-ˈā-shən How to pronounce radiation (audio) \

Medical Definition of radiation

1 : energy radiated in the form of waves or particles
2a : the action or process of radiating with radiation of the pain there may be tenderness over the sciatic nerve— J. A. Key
b(1) : the process of emitting radiant energy in the form of waves or particles
(2) : the combined processes of emission, transmission, and absorption of radiant energy
3 : a tract of nerve fibers within the brain especially : one concerned with the distribution of impulses arising from sensory stimuli to the relevant coordinating centers and nuclei the optic radiations

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More from Merriam-Webster on radiation

Rhyming Dictionary: Words that rhyme with radiation

Spanish Central: Translation of radiation

Nglish: Translation of radiation for Spanish Speakers

Britannica English: Translation of radiation for Arabic Speakers

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