tau

Meanings

Plural: taus

Noun

the 19th letter of the Greek alphabet
The letter Τ /τ in the Greek alphabet; being the nineteenth letter of the Classical and Modern Greek, and the twenty-first letter of the Old and Ancient Greek alphabets.
Alternative form of taw; the 22nd and last letter of many Semitic alphabets/abjads, including Phoenician, Aramaic, Hebrew, Syriac, and Arabic.
A Τ-shaped object or sign; a Saint Anthony's cross, sometimes regarded as a sacred symbol.
A Τ-shaped object or sign; a Saint Anthony's cross, sometimes regarded as a sacred symbol.
A crosier with a Τ-shaped head.
The ankh symbol (☥).
Chiefly written τ: used to designate the nineteenth star (usually according to brightness) in a constellation.
A measurement of the sensitivity of the value of an option to changes in the implied volatility of the price of the underlying asset.
Chiefly written τ: an irrational and transcendental constant representing the ratio of the circumference of a Euclidean circle to its radius, equal to twice the value of pi (2π; approximately 6.2831853071).
Ellipsis of tau protein (“a protein abundant especially in the neurons of the human central nervous system that stabilizes microtubules, and when misfolded is associated with forms of dementia such as Alzheimer's and Parkinson's diseases”).
Chiefly written τ.
Ellipsis of tau lepton or tau particle (“an unstable elementary particle which is a type of lepton, having a mass almost twice that of a proton, a negative charge, and a spin of ½; it decays into hadrons (usually pions) or other leptons, and neutrinos; a tauon”).
Chiefly written τ.
Ellipsis of tau meson, now known as a kaon.

Origin / Etymology

From Middle English tau, taue, from Latin tau, from Ancient Greek ταῦ (taû) and Hebrew תָּו (tav).
Sense 6 (“mathematical constant equal to 2π”) was used by Joseph M. Lindenberg in 1991, and popularized by the American educator and entrepreneur Michael Hartl in a 2010 paper which explains that τ resembles π; and that τ is the Greek equivalent of t, the first letter of turn, and 2π corresponds to one turn of a circle with a radius of one unit.
Sense 8.1 (“ellipsis of tau lepton or tau particle”) was coined by the American physicist Martin Lewis Perl (1927–2014) after the first letter of Ancient Greek τρίτον (tríton, “third”), since the tau lepton or tauon was the third charged lepton discovered.

Synonyms

crux ansata, kappa, vega

Scrabble Score: 3

tau is a valid Scrabble (US) TWL word
tau is a valid Scrabble Word in Merriam-Webster MW Dictionary
tau is a valid Scrabble Word in International Collins CSW Dictionary

Words With Friends Score: 4

tau is a valid Words With Friends word