definitions
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radiation

[ rey-dee-ey-shuh n ]
/ ˌreɪ diˈeɪ ʃən /
|
SEE MORE SYNONYMS FOR radiation ON THESAURUS.COM

noun

Physics.
  1. the process in which energy is emitted as particles or waves.
  2. the complete process in which energy is emitted by one body, transmitted through an intervening medium or space, and absorbed by another body.
  3. the energy transferred by these processes.
the act or process of radiating.
something that is radiated.
radial arrangement of parts.

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RELATED WORDS

emission, radioactivity, diffusion, circulation, transmission, divergence, broadcast, dispersion, propagation, spread, ramification, dispersal, dissipation, distribution, scattering, divarication, polarization, diffraction

Nearby words

radiata, radiata pine, radiate, radiate crown, radiate ligament of rib, radiation, radiation belt, radiation biology, radiation damage, radiation dermatitis, radiation fog

Origin of radiation

1545–55; < Latin radiātiōn- (stem of radiātiō) a glittering, shining. See radiate, -ion
Related formsra·di·a·tion·al, adjectivean·ti·ra·di·a·tion, adjectivein·ter·ra·di·a·tion, nounnon·ra·di·a·tion, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for radiation

British Dictionary definitions for radiation

radiation

/ (ˌreɪdɪˈeɪʃən) /

noun

physics
  1. the emission or transfer of radiant energy as particles, electromagnetic waves, sound, etc
  2. the particles, etc, emitted, esp the particles and gamma rays emitted in nuclear decay
Also called: radiation therapy med treatment using a radioactive substance
anatomy a group of nerve fibres that diverge from their common source
See adaptive radiation
the act, state, or process of radiating or being radiated
surveying the fixing of points around a central plane table by using an alidade and measuring tape
Derived Formsradiational, adjective
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for radiation

radiation

n.

mid-15c., "act or process of radiating," from Middle French radiation and directly from Latin radiationem (nominative radiatio) "a shining, radiation," noun of action from past participle stem of radiare "to beam, shine, gleam; make beaming," from radius "beam of light; spoke of a wheel" (see radius). Meaning "rays or beams emitted" is from 1560s. Meaning "divergence from a center" is 1650s.

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for radiation

radiation

[ rā′dē-ā′shən ]

n.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for radiation

radiation

[ rā′dē-ā′shən ]

  1. Streams of photons, electrons, small nuclei, or other particles. Radiation is given off by a wide variety of processes, such as thermal activity, nuclear reactions (as in fission), and by radioactive decay.
  2. The emission or movement of such particles through space or a medium, such as air. See Notes at conduction electromagnetic radiation.
The use of such energy, especially x-rays, in medical diagnosis and treatment.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Culture definitions for radiation

radiation

Energy sent out in the form of particles or waves. (See alpha radiation, beta radiation, blackbody, cosmic rays, electromagnetic radiation, fluorescence, gamma radiation, photon, and quanta.)

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.