theta
Americannoun
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the eighth letter of the Greek alphabet (Θ, θ).
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the consonant sound represented by this letter.
noun
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the eighth letter of the Greek alphabet (Θ, θ), a consonant, transliterated as th
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the lower-case form of this letter used in phonetic transcription to represent the voiceless dental fricative th as in thick, both Compare edh
Etymology
Origin of theta
1595–1605; < Greek thêta < Semitic See teth
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Then by 2½ minutes, slower-frequency theta waves related to deep inner stillness increased.
From The Wall Street Journal ● Jun. 27, 2026
EEG analysis revealed that pairs of strangers exhibited greater intra-brain synchronization in the theta band, compared to acquainted pairs.
From Science Daily ● Apr. 23, 2024
Richard Wood, PhD, a distinguished professor at University of Texas MD Anderson Cancer Center played a key role in the first characterization of polymerase theta in 2003.
From Science Daily ● Nov. 15, 2023
The five common brain-wave types, named alpha, beta, gamma, delta and theta depending on their oscillation rate, signify different states of the brain.
From Scientific American ● Jun. 16, 2023
The EEG research found intensification over time of theta waves in the prefron- tal cortex, thought to be a measure of sustained attention.
From "A Deadly Wandering: A Mystery, a Landmark Investigation, and the Astonishing Science of Attention in the Digital Age" by Matt Richtel
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.