from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A stream of ionizing radiation of extraterrestrial origin, consisting chiefly of protons, alpha particles, and other atomic nuclei but including some high-energy electrons, that enters the atmosphere, collides with atomic nuclei, and produces secondary radiation, principally pions, muons, electrons, and gamma rays.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An energetic particle originating outside our solar system.
- n. Cosmic radiation: a stream of cosmic rays.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. highly penetrating ionizing radiation of extraterrestrial origin; consisting chiefly of protons and alpha particles; collision with atmospheric particles results in rays and particles of many kinds
Sorry, no etymologies found.