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English definition of “radiation”

radiation

noun [U] uk   /ˌreɪ.diˈeɪ.ʃən/ us  
C1 a form of energy that comes from a nuclear reaction and that can be very dangerous to health: Many servicemen suffered radiation sickness after the early atomic tests.Radiation and radioactivity energy from heat or light that you cannot see: microwave/ultraviolet/electromagnetic radiationRadiation and radioactivity
(Definition of radiation from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
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