theta

[ they-tuh, thee- ]

/ ˈθeɪ tə, ˈθi- /

Save This Word!

noun

the eighth letter of the Greek alphabet (Θ, θ).

the consonant sound represented by this letter.

QUIZ

CAN YOU ANSWER THESE COMMON GRAMMAR DEBATES?

There are grammar debates that never die; and the ones highlighted in the questions in this quiz are sure to rile everyone up once again. Do you know how to answer the questions that cause some of the greatest grammar debates?

Question 1 of 7

Which sentence is correct?

His boss, whom he admires, is waiting to meet with him about the big project.

His boss, who he admires, is waiting to meet with him about the big project.

TAKE THE QUIZ TO FIND OUT

Origin of theta

1595–1605; <Greek thêta<Semitic See teth

Words nearby theta

Sun Also Rises, The, Suppliants, The, Swan Lake, The, The Swiss Family Robinson, The Symposium, theta, tail wagging the dog, the, Tale of Genji, The, talk of the town, the, Taming of the Shrew, The, theta rhythm

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use theta in a sentence

Horses that roamed with their herd, grazing outdoors at will, had more theta brainwaves.
Science is just starting to understand what animals feel|Alla Katsnelson|October 6, 2022|Science News For Students
Theta waves, in contrast, correlate with daydreaming—a sort of mental relaxation.
Metasurfaces Open the Door to Telekinesis and Telepathy With Technology|Shelly Fan|June 28, 2022|Singularity Hub
We can see this with decreased theta brain waves in the hippocampus, which is necessary to retrieve memories, the authors explained.
The Brain Has a Built-in System to Keep Unwanted Memories Out, Study Finds|Shelly Fan|May 3, 2022|Singularity Hub
The region then further smothers theta waves in the hippocampus in an effort to stop intrusive thoughts.
The Brain Has a Built-in System to Keep Unwanted Memories Out, Study Finds|Shelly Fan|May 3, 2022|Singularity Hub

Theta waves, which wash over the hippocampus, trigger a state in the brain that’s prone to a flow of ideas—à la “shower thoughts.”
How Virtual Reality Unveiled a Unique Brain Wave That Could Boost Learning|Shelly Fan|July 6, 2021|Singularity Hub
As vice president of Theta, I was tasked with figuring out how to get members more involved.
Frat Culture's Woman Problem|Samantha Wishman|April 22, 2011|DAILY BEAST
In Scientology parlance, good news is theta news; entheta is the opposite.
Is Scientology's Wall Cracking?|Kim Masters|June 28, 2009|DAILY BEAST
The Gothic alphabet, in fact, as used in this country, had a Theta for expressing in one letter our present t and h conjoined.
The Book-Hunter|John Hill Burton
The Theta Gammas wrote her down as material for a quaint little, quiet little dig,—not of sorority interest.
Stanford Stories|Charles K. Field
We'll go back to 29, and put in sine squared theta minus one equal to z sub four.
Spacehounds of IPC|Edward Elmer Smith
In order to make any solution at all possible you have assumed cosine squared theta negligible.
Spacehounds of IPC|Edward Elmer Smith
He maintained, however, that he had noticed Theta Cancri as well as the two planets, but without recording its position.
The Story of the Heavens|Robert Stawell Ball

British Dictionary definitions for theta

theta

/ (ˈθiːtə) /

noun

the eighth letter of the Greek alphabet (Θ, θ), a consonant, transliterated as th

the lower-case form of this letter used in phonetic transcription to represent the voiceless dental fricative th as in thick, bothCompare edh

Word Origin for theta

C17: from Greek, of Semitic origin; compare Hebrew tēth

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012