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[they-tuh, thee-] /ˈθeɪ tə, ˈθi-/
the eighth letter of the Greek alphabet (Θ, θ).
the consonant sound represented by this letter.
Origin of theta
1595-1605; < Greek thêta < Semitic See teth Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the Web for theta
Contemporary Examples
Historical Examples
  • Next to Aldebaran in the V is the interesting double star theta, which we can see as two distinct stars without a telescope.

    Astronomy for Young Folks Isabel Martin Lewis
  • Under the signature of theta, he has since been a regular contributor of verses to that journal.

  • The Latin language, wanting both the sound of the Greek theta, and the sign to express it (θ) rendered it by th.

    The English Language Robert Gordon Latham
  • "theta" he called this piece of canvas, which was a large square painting representing, in the foreground, the death of Socrates.

    Macaria Augusta Jane Evans Wilson
  • A tree in a prairie on a celestial body, as far as theta of Orion is from Capella, is perfectly visible to us.

    Lumen Camille Flammarion
  • The theta Gammas wrote her down as material for a quaint little, quiet little dig,—not of sorority interest.

    Stanford Stories Charles K. Field
  • 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
  • You understand me—you know what is lacking; finish my 'theta' and tell the world I died at work upon it.

    Macaria Augusta Jane Evans Wilson
British Dictionary definitions for theta


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, both Compare edh
Word Origin
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
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Word Origin and History for theta

eighth letter of the Greek alphabet; in ancient Greece, written on ballots to indicate a vote for a sentence of "death" (thanatos), hence occasional allusive use for "death."

Online Etymology Dictionary, © 2010 Douglas Harper
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theta in Medicine

theta the·ta (thā'tə, thē'-)

Symbol θ The eighth letter of the Greek alphabet.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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