from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Energy transferred by radiation, especially by an electromagnetic wave.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Energy in a form that can radiate, generally electromagnetic energy.
from the GNU version of the Collaborative International Dictionary of English
- adj. energy given out or transmitted by radiation, as in the case of light and radiant heat.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. energy that is transmitted in the form of (electromagnetic) radiation; energy that exists in the absence of matter
Sorry, no etymologies found.
Planck suggested that radiant energy exists only in discrete packages that he called quanta.