- irradiate [ir rā′dēāt΄, i rā′dēāt΄; ] for adj., usually [, i rā′dēit]vt.irradiated, irradiating [< L irradiatus, pp. of irradiare, to beam upon, illumine: see IN-1 & RADIATE]1. to shine or throw light upon; light up; make bright2. to make clear; illuminate intellectually; enlighten3. to radiate; diffuse; spread; give out4. to expose to or treat by exposing to X-rays, ultraviolet rays, radium, or some other form of radiant energy5. to heat with radiant energyvi.1. to emit rays; shine2. to become radiantadj.lighted up; irradiatedirradiativeadj.irradiatorn.
English World dictionary. V. Neufeldt. 2014.