Толковый словарь английского языка Oxford English Reference - radiation

n. 1 the act or an instance of radiating; the process of being radiated. 2 Physics a the emission of energy as electromagnetic waves or as moving particles. b the energy transmitted in this way, esp. invisibly. 3 (in full radiation therapy) treatment of cancer and other diseases using radiation, such as X-rays or ultraviolet light. Phrases and idioms radiation chemistry the study of the chemical effects of radiation on matter. radiation sickness sickness caused by exposure to radiation, such as X-rays or gamma rays. Derivatives radiational adj. radiationally adv. Etymology: L radiatio (as RADIATE)