from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A slow brain wave, having a frequency of fewer than six cycles per second, that emanates from the forward portion of the brain and is associated with deep sleep in normal adults. Also called delta rhythm.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the normal brainwave in the encephalogram of a person in deep dreamless sleep; occurs with high voltage and low frequency (1 to 4 hertz)
Sorry, no etymologies found.