noun
the normal brainwave in the encephalogram of a person in deep dreamless sleep; occurs with high voltage and low frequency (1 to 4 hertz)
• Syn: ↑delta rhythm
• Hypernyms: ↑brainwave, ↑brain wave, ↑cortical potential
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noun also delta or delta rhythm : a high amplitude electrical rhythm of the brain with a frequency of less than 6 cycles per second that occurs especially in deep sleep, in infancy, and in many diseased conditions of the brain
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Physiol.
any of the slow brain waves constituting delta rhythm.
[1935-40]
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delta rhythm or delta wave noun
One of the waves recorded on an electroencephalogram indicating the low-frequency brain activity of a sleeping person
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Main Entry: ↑delta
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delta wave,
a large, slow brain wave marking the deepest level of sleep: »
High-amplitude delta waves in sleep are almost typical of youth. With increasing age, however, the EEG [electroencephalogram] of the delta waves becomes smaller and flatter (Segal and Luce).
Useful english dictionary. 2012.