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

The effort is part of the ambitious SIGMA+ project, which has already deployed inexpensive handheld nuclear weapon and radiation detectors. Dan Dubno, Popular Mechanics, "How We'll Stop Chemical Attacks," 28 Apr. 2019 Workers who enter areas with elevated radiation would need sufficient Japanese-language skills... Mayumi Negishi, WSJ, "Japan Aims to Hire Foreigners for Nuclear Cleanup," 18 Apr. 2019 But that wisdom will change, as researchers have shown how to make a lens for extreme ultraviolet radiation. Chris Lee, Ars Technica, "Gas jets make beautiful lens for light we can’t normally focus," 21 Dec. 2018 At these sites, Hoecker has embedded sensors in the ground to collect data on soil temperature and moisture, while meteorological stations at each site collect data on air temperature, humidity and solar radiation. Kristen Pope, Discover Magazine, "Wildfire Engulfed Yellowstone 30 Years Ago. Its Recovery Could Predict The Future of the West," 12 Nov. 2018 The Daiichi Nuclear Power Station, where the 2011 meltdown occurred in the wake of a 7.0-magnitude earthquake, is 75 miles east, separated by several mountain ridges that prevented dangerous radiation from reaching this area. Adam H. Graham, Condé Nast Traveler, "Slow Skiing in Japan's Deep North," 11 Oct. 2018 Treatment for anal cancer usually involves a combination of radiation and chemotherapy, which can indeed result in hair loss. Korin Miller, SELF, "‘Desperate Housewives’ Star Marcia Cross Reveals She’s in Recovery After Anal Cancer Treatment," 28 Sep. 2018 Treatment typically involves surgery to remove the tumor, followed by radiation and chemotherapy to make sure the cancer doesn’t return. Soumya Karlamangla, latimes.com, "Their daughter was diagnosed with an aggressive brain tumor. Two weeks later, their son was too," 28 June 2018 Methane is quickly broken down by radiation, so it must be replenished by some source on the planet. Sarah Kaplan, BostonGlobe.com, "Newest NASA discoveries could boost search for ancient life on Mars," 8 June 2018

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

21 May 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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