The name in English is pronounced/taʊ/ or/tɔː/,[2] but inGreek it is[taf].[3][4] This is because the pronunciation of the combination of Greek letters αυ can have the pronunciation of either[ai],[av] or[af], depending on what follows and if adiaeresis is present on the second vowel (seeGreek orthography).
Tau was derived from thePhoenician lettertaw (𐤕).[5] Letters that arose from tau include RomanT and CyrillicTe (Т, т).
The expressed period of thefreerunning rhythm of an animal, i.e., the length of the daily cycle of an animal when kept in constant light or constant darkness
In ancient times, tau was used as a symbol forlife orresurrection, whereas the eighth letter of the Greek alphabet,theta, was considered the symbol ofdeath.[citation needed]
In Biblical times, thetaw was put on men to distinguish those who lamented sin, although newer versions of the Bible have replaced the ancient termtaw withmark (Ezekiel 9:4) orsignature (Job 31:35). Its original sound value is avoiceless alveolar plosive, IPA /t/[citation needed]
The symbolism of thecross was connected not only to the letterchi but also to tau, the equivalent of the last letter in thePhoenician and Old Hebrew alphabets, and which was originally cruciform in shape; seeCross of Tau.[citation needed]
Men weep, and bewail their lot, and curse Cadmus with many curses for introducingTau into the family of letters; they say it was his body that tyrants took for a model, his shape that they imitated, when they set up structures on which men are crucified.Stauros (cross) the vile engine is called, and it derives its vile name from him. Now, with all these crimes upon him, does he not deserve death, nay, many deaths? For my part I know none bad enough but that supplied by his own shape — that shape which he gave to thegibbet namedstauros after him by men
Tau is usually considered as the symbol ofFranciscan orders due toSt. Francis' love for it, symbol of the redemption and of theCross. Almost all Franciscan churches have painted a tau with two crossing arms, both withstigmata, the one of Jesus and the other of Francis; members of theSecular Franciscan Order usually wear a wooden τ in a string with three knots around the neck
The title and symbol of "Tau" is used byneo-Gnostic bishops as it has some symbolism in many of the modern branches of Gnosticism.
For the unofficial astronomical symbol ofSaturn’s moon ofTitan, a ringed tau is connected to the crook of Saturn.
U+1D7A3𝞣MATHEMATICAL SANS-SERIF BOLD ITALIC CAPITAL TAU
U+1D7BD𝞽MATHEMATICAL SANS-SERIF BOLD ITALIC SMALL TAU
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^C, González; G, Farías; RB, Maccioni (1 Nov 1998). "Modification of tau to an Alzheimer's type protein interferes with its interaction with microtubules".Cell Mol Biol (Noisy-le-grand).44 (7):1117–1127.PMID9846894 – via EuropeMC.
^M, Sjögren; E, Englund (2004). "Negative neurofilament light and tau immunostaining in frontotemporal dementia".Dementia and Geriatric Cognitive Disorders.17 (4):346–349.doi:10.1159/000077169.PMID15178951.S2CID9306507.
^Weisstein, Eric W. (27 Oct 2017)."Divisor Function".mathworld.wolfram.com.Archived from the original on 29 Jun 2017. Retrieved28 Oct 2017.
^Weisstein, Eric W."Tau Function".mathworld.wolfram.com. Retrieved2025-01-31.A functionτ(n) related to the divisor functionσ(n), also sometimes called Ramanujan's tau function.
^Weisstein, Eric W."Torsion".Wolfram MathWorld.Archived from the original on 29 Aug 2017. Retrieved28 Oct 2017.
^Weisstein, Eric W."Thue-Morse Sequence".mathworld.wolfram.com. Retrieved2025-01-31.The Thue–Morse sequence, also called the Morse–Thue sequence or Prouhet–Thue–Morse sequence (Allouche and Cosnard 2000), is one of a number of related sequences of numbers obtained from the parities of the counts of 1's in the binary representation of the nonnegative integers.
^Elert, Glenn (2023),"Special Symbols",The Physics Hypertextbook, hypertextbook, retrieved2025-02-01,τ time constant
^Weisstein, Eric W."Tau".mathworld.wolfram.com. Retrieved2025-02-01.The symbol also has a number of other different meanings in physics, for example the tau particle, tau neutrino, as a symbol for torque, etc.
