tau

American  

[tou, taw, tahv, tawv] / taʊ, tɔ, tɑv, tɔv /

noun

1. the 19th letter of the Greek alphabet (T,τ ).

2. the consonant sound represented by this letter.

3. tav.

4. Physics. Also tauon tau lepton.

5. 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.

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tau British  

/ taʊ, tɔː /

noun

1. the 19th letter in the Greek alphabet (Τ, τ), a consonant, transliterated as t

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Etymology

Origin of tau

1250–1300; Middle English < Latin < Greek taû < Semitic; cf. tav

Example Sentences

If diranersen can rise above these concerns and go to market, it will be the first treatment that targets the tau protein.

From Barron's • May 14, 2026

Biogen’s diranersen demonstrated robust reductions in tau protein levels and buildup in a Phase 2 Alzheimer’s trial.

From Barron's • May 14, 2026

A tiny parasitic wasp - the Attenboroughnculus tau - was also named in his honour, although it is far from his first fauna namesake.

From BBC • May 9, 2026

The Attenboroughnculus tau is native to the Patagonian lakes of Chile, and a specimen was recently found in the museum's collection, four decades after it was collected.

From BBC • May 7, 2026

We have also Buxtorff for us, who in his Hebrew Lexicon turneth tau to signum, and for this signification he citeth both this place, Ezek. ix.

From The Works of Mr. George Gillespie (Vol. 1 of 2) by Gillespie, George