/ ɪˈreɪdieɪt; NAmE / verb [ vn ]
1.
( technical ) to treat food with gamma radiation in order to preserve it
2.
irradiate sth (with sth) ( literary ) to make sth look brighter and happier :
faces irradiated with joy
► ir·radi·ation / ɪˌreɪdiˈeɪʃn; NAmE / noun [ U ]
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WORD ORIGIN
late 16th cent. (in the sense emit rays, shine upon ): from Latin irradiat- shone upon, from the verb irradiare , from in- upon + radiare to shine (from radius ray).