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1. Energy that is radiated or transmitted in the form of rays or waves or particles
    
2. The act of spreading outward from a central source
    
3. Syndrome resulting from exposure to ionizing radiation (e.g., exposure to radioactive chemicals or to nuclear explosions); low doses cause diarrhoea and nausea and vomiting and sometimes loss of hair; greater exposure can cause sterility and cataracts and some forms of cancer and other diseases; severe exposure can cause death within hours
   "he was suffering from radiation";
   - radiation sickness, radiation syndrome
    
4. The spontaneous emission of a stream of particles or electromagnetic rays in nuclear decay
   - radioactivity
    
5. The spread of a group of organisms into new habitats
    
6. A radial arrangement of nerve fibers connecting different parts of the brain
    
7. (medicine) the treatment of disease (especially cancer) by exposure to a radioactive substance
   "radiosensitive cancer cells can be treated with radiation";
   - radiotherapy, radiation therapy, actinotherapy, irradiation

Derived forms: radiations

Type of: action, activity, emanation, emission, energy, free energy, natural action, natural process, neural structure, spread, spreading, syndrome, therapy, treatment

Encyclopedia: Radiation, nuclear