noun (n)

• the condition of being exposed to radiation(noun.state)

  source: wordnet30
• a column of light (as from a beacon)(noun.phenomenon)

  Synonym:
  beam, beam of light, light beam, ray, ray of light, shaft, shaft of light
  

  source: wordnet30
• (physiology) the spread of sensory neural impulses in the cortex(noun.event)

  source: wordnet30
• the apparent enlargement of a bright object when viewed against a dark background(noun.cognition)

  source: wordnet30
• (Pavolvian conditioning) the elicitation of a conditioned response by stimulation similar but not identical to the original stimulus(noun.cognition)

  source: wordnet30
• (medicine) the treatment of disease (especially cancer) by exposure to a radioactive substance(noun.act)

  Synonym:
  actinotherapy, radiation, radiation therapy, radiotherapy
  

  source: wordnet30
• Act of irradiating, or state of being irradiated.(noun)

  source: webster1913