radiation

Radiation has 4 syllables: ra · di · a · tion.

noun. The spontaneous emission of a stream of particles or electromagnetic rays in nuclear decay.

noun. Syndrome resulting from exposure to ionizing radiation (e.g., exposure to radioactive chemicals or to nuclear explosions); low doses cause diarrhea 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.

noun. (medicine) the treatment of disease (especially cancer) by exposure to a radioactive substance.

noun. A radial arrangement of nerve fibers connecting different parts of the brain.