What is the meaning of irradiation?

noun

• The condition of being exposed to radiation.
• A column of light (as from a beacon.
  • synonyms: beam, beam of light, light beam, ray, ray of light, shaft, shaft of light
• Physiology) the spread of sensory neural impulses in the cortex. (
• The apparent enlargement of a bright object when viewed against a dark background.
• Pavolvian conditioning. ( the elicitation of a conditioned response by stimulation similar but not identical to the original stimulus)
• Medicine) the treatment of disease (especially cancer) by exposure to a radioactive substance. (.
  • synonyms: radiotherapy, radiation therapy, radiation, actinotherapy