Radiation - Definition

n 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 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; "he was
suffering from radiation" [syn: radiation sickness,
radiation syndrome, radiation]
4: the spontaneous emission of a stream of particles or
electromagnetic rays in nuclear decay [syn: radiation,
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 [syn: radiotherapy,
radiation therapy, radiation, actinotherapy,
irradiation]