theta

noun
the·​ta | \ ˈthā-tə How to pronounce theta (audio) , chiefly British ˈthē-tə \

Definition of theta

1 : the 8th letter of the Greek alphabet — see Alphabet Table

Examples of theta in a Sentence

Recent Examples on the Web For example, if an option’s theta is minus 0.20, an investor can expect its premium to decline, or decay, 20 cents a day, if everything else remains constant. Nick Ravo, WSJ, "These Options Terms Are Greek to You," 5 Oct. 2020 The theta cycles seem to be a clear entry point to unraveling how that works. Quanta Magazine, "In Brain Waves, Scientists See Neurons Juggle Possible Futures," 24 Feb. 2020 The angle — θ, or theta — could have ranged anywhere from zero to 360 degrees, representing degrees of difference between quarks and mirror-image antiquarks. Quanta Magazine, "Axions Would Solve Another Major Problem in Physics," 17 Mar. 2020 Perhaps most tellingly, says Sirigu, the man’s brain began producing stronger theta waves, electrical brain rhythms correlated with consciousness. Michael Price, Science | AAAS, "Experimental nerve-stimulation therapy partially revives man in long-term vegetative state—but experts urge caution," 25 Sep. 2017 The researchers are using a form of rTMS called intermittent theta burst stimulation, in which pulses are delivered in bursts, like machine-gun fire. Meredith Wadman, Science | AAAS, "Brain-altering magnetic pulses could zap cocaine addiction," 29 Aug. 2017 Psychologists at Oregon speculated that the surge in theta waves stimulated the production of cells in the white matter. Gretchen Reynolds, New York Times, "Of Mice and Mindfulness," 18 May 2017 The Oregon group, by pulsing the light at the same frequency found in human theta waves (eight hertz), were able to switch on the neurons in the anterior cingulate cortexes of the mice. Gretchen Reynolds, New York Times, "Of Mice and Mindfulness," 18 May 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'theta.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of theta

15th century, in the meaning defined at sense 1

History and Etymology for theta

Middle English, from Latin, from Greek thēta, of Semitic origin; akin to Hebrew ṭēth teth

Keep scrolling for more

Learn More about theta

Time Traveler for theta

Time Traveler

The first known use of theta was in the 15th century

See more words from the same century

Statistics for theta

Last Updated

13 Oct 2020

Cite this Entry

“Theta.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/theta. Accessed 27 Oct. 2020.

Comments on theta

What made you want to look up theta? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

Test Your Vocabulary

Namesakes Word Quiz

  • a citrus fruit possibly named after a person
  • Which of the following is a fruit named after a Moroccan seaport?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Bee Cubed

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!