radiation

noun
ra·​di·​a·​tion | \ ˌrā-dē-ˈā-shən \

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

Keep scrolling for more

Other Words from radiation

radiational \ ˌrā-​dē-​ˈā-​shnəl , -​shə-​nᵊl \ adjective
radiationless \ ˌrā-​dē-​ˈā-​shən-​ləs \ adjective
radiative \ ˈrā-​dē-​ˌā-​tiv \ 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
See More

Recent Examples on the Web

After that delay, KickSat-1 failed to discharge its Sprites because of an electrical problem likely caused by exposure to radiation. Steve Nadis, Discover Magazine, "The Tiny Satellites That Might Fly to Another Solar System," 18 Oct. 2018 According to Mayo Clinic, basal cell carcinoma is a type of skin cancer that is thought to be caused by long-term exposure to ultraviolet radiation from sunlight. Temi Adebowale, Good Housekeeping, "Melanie Griffith Makes Plea to Fans After Revealing "Final Stage" to Remove Skin Cancer," 27 Aug. 2018 That includes those with a family history or previous radiation treatment to the chest wall. Laura Landro, WSJ, "A New Push to Lower Your Risk for Breast Cancer," 3 Oct. 2018 The Ministry has tied four illnesses to radiation exposure from the Fukushima disaster. Megan Geuss, Ars Technica, "Japan acknowledges first radiation-linked death out of Fukushima," 5 Sep. 2018 Some of the radiation exposure came through food grown in the affected areas. Nate Poppino, idahostatesman, "Nuclear tests gave these Idahoans cancer, they say. Will Congress support them now?," 27 June 2018 Beyond the unacceptable immediate deaths from nuclear weapons, millions more would die from radiation exposure and resulting famine. Beatrice Fihn, Time, "Ending War Games With South Korea Isn't a 'Stunning Concession.' It's the Best Thing to Come Out of the Summit So Far," 13 June 2018 About half of potential radiation exposure occurs within the first hour, and 80 percent occurs within the first day. Daily Intelligencer, "This Is What a Nuclear Bomb Looks Like," 12 June 2018 Aging is a multifactorial process and is heavily influenced by genetics, UV radiation exposure, and stress. Adam Hurly, GQ, "This Is How Sleep Deprivation Affects Your Appearance," 9 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.

See More

First Known Use of radiation

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

Keep scrolling for more

Learn More about radiation

Statistics for radiation

Last Updated

15 Jan 2019

Look-up Popularity

Time Traveler for radiation

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

See more words from the same century

Keep scrolling for more

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 \

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 \

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

Keep scrolling for more

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

Comments on radiation

What made you want to look up radiation? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

to gather or build up little by little

Get Word of the Day daily email!

Test Your Vocabulary

Homophone Quiz

  • three-bears-two-of-them-look-like-theyre-whispering-to-a-third-bear-who-looks-chuffed-to-be-the-center-of-attention
  • In order to judge how people felt, the senator's office hired a firm to take a ______.
Name That Thing

Test your visual vocabulary with our 10-question challenge!

TAKE THE QUIZ
Syn City

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!