irradiation (Noun) — The condition of being exposed to radiation.
irradiation (Noun) — A column of light (as from a beacon).
irradiation (Noun) — (physiology) the spread of sensory neural impulses in the cortex.
irradiation (Noun) — The apparent enlargement of a bright object when viewed against a dark background.
irradiation (Noun) — (Pavlovian conditioning) the elicitation of a conditioned response by stimulation similar but not identical to the original stimulus.
irradiation (Noun) — (medicine) the treatment of disease (especially cancer) by exposure to a radioactive substance.