from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A waveform on an electroencephalogram having a frequency of 4 to 8 hertz, recorded chiefly in the hippocampus of carnivorous mammals when they are alert or aroused. Also called theta wave.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A type of electrical activity in the brain, brain waves with a frequency 4-8 hertz.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the normal brainwave in the encephalogram of a person who is awake but relaxed and drowsy; occurs with low frequency and low amplitude
theta + rhythm (Wiktionary)