[ir.ra.di.ate] vb -at.ed ; -at.ing [L irradiatus, pp. of irradiare, fr. in- + radius ray] vt (1603) 1 a: to cast rays of light upon: illuminate b: to enlighten intellectually or spiritually c: to affect or treat by radiant energy (as heat); specif: to treat by exposure to radiation
2: to emit like rays of light: radiate "irradiating strength and comfort" ~ vi, archaic: to emit rays: shine -- ir.ra.di.a.tive adj -- ir.ra.di.a.tor n