- any of the brain waves constituting theta rhythm.
Origin of theta wave
First recorded in 1965–70
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- 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.theta rhythm