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[tou, taw for 1, 2, 4; tahv, tawv for 3] /taʊ, tɔ for 1, 2, 4; tɑv, tɔv for 3/
the 19th letter of the Greek alphabet (T, τ).
the consonant sound represented by this letter.
Also, tauon [tou-on] /ˈtaʊ ɒn/ (Show IPA). Physics. tau lepton.
Also called tau protein. Biochemistry. a protein that is an important component of nerve cells, helping to maintain their function and structure: in the brain, distortions in the protein’s molecular shape is associated with the onset of Alzheimer’s disease.
Origin of tau
1250-1300; Middle English < Latin < Greek taû < Semitic; cf. tav Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2018.
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Examples from the Web for tau
Contemporary Examples
Historical Examples
  • It is an embryonic form, and therefore inferior in rank to the tau moth.

    Our Common Insects Alpheus Spring Packard
  • Now Ra-Molo had a brother who bore the name of tau (the lion).

    Basutoland Minnie Martin
  • The pastures of tau through the mist; the mist is distinctly visible.

    A Tour Through The Pyrenees Hippolyte Adolphe Taine
  • It is noticeable that the Christian flag bears the tau Cross.

  • This tau was unquestionably the emblem of life, and, therefore, of the greatest virtue.

    Evolution in Art Alfred C. Haddon
  • The hieroglyphics on it mean doubtless the sacred word 'tau.'

    A Son of Perdition

    Fergus Hume
  • At their approach the idols vanish, and the priests of Buddh and tau disappear.

  • When all was finished, Melu and tau Tana whipped the forms until they moved.

    Philippine Folk Tales Mabel Cook Cole
British Dictionary definitions for tau


/tɔː; taʊ/
the 19th letter in the Greek alphabet (Τ, τ), a consonant, transliterated as t
Word Origin
C13: via Latin from Greek, of Semitic origin; see tav
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 tau

nineteenth letter of the Greek alphabet, from Hebrew taw, last letter of the Hebrew alphabet, literally "sign, mark."

Online Etymology Dictionary, © 2010 Douglas Harper
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tau in Medicine

tau n.

Symbol τ The 19th 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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