tau
/taʊ/noun
tau is spelled T-A-U: 3 letters. It appears 1.9 times per million words in written English, the 19,825th most frequent word form (wordfreq, 2021 data). As a noun, tau means “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…” (English Wiktionary, September 2026). The plural of tau is taus.
How many letters and syllables are in tau?
| Letters | 3: T-A-U |
|---|---|
| In writing | 1.9 times per million words; the 19,825th most frequent word form |
| Wrong spellings searched | none measured in search |
| Rhymes with | |
| Same letters |
Sources: letters and syllables from the English Wiktionary's hyphenation or pronunciation; written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media); rhymes and same-letter words are computed by PlainSpell from its own word list.
How common is tau?
Tau appears 1.9 times per million words in written English, the 19,825th most frequent word form in the list.
Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
How do you pronounce tau?
- UK /taʊ/
- UK /tɔː/
- US /taʊ/
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Recordings: En-us-tau.ogg, Wikimedia Commons (author and licence on each file's page).
Words people confuse with tau
Also written: taw.
Sources: English Wiktionary (homophones, alternative spellings).
What rhymes with tau?
The 12 most written words on PlainSpell end in the same sounds as tau from its last stressed vowel (/aʊ/):
Spelled with the same letters in another order: uta.
Computed by PlainSpell from the pronunciations in the English Wiktionary (dump of September 2, 2026): a rhyme shares every sound from the last stressed vowel to the end; ordered by written frequency (wordfreq 3.1).
Forms of tau
- taus plural
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).
What does tau mean?
The meanings the English Wiktionary records, quoted as written there (source below).
noun
- 1
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.
- 2
Alternative form of taw; the 22nd and last letter of many Semitic alphabets/abjads, including Phoenician, Aramaic, Hebrew, Syriac, and Arabic.
- 3
A Τ-shaped object or sign; a Saint Anthony's cross, sometimes regarded as a sacred symbol.
- 4
A crosier with a Τ-shaped head.
- 5
The ankh symbol (☥).
- 6
Chiefly written τ: used to designate the nineteenth star (usually according to brightness) in a constellation.
- 7
A measurement of the sensitivity of the value of an option to changes in the implied volatility of the price of the underlying asset.
(includes a list of coordinate terms)
- 8
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).
noun
- 1
Abbreviation of treatment as usual.
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).
Tau in Spanish, French, German and Portuguese
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Translations are Wiktionary's, by sense; a linked word has its own PlainSpell page.
Where does tau come from?
From Middle English tau, taue, from Latin tau, from Ancient Greek ταῦ (taû) and Hebrew תָּו (tav). Sense 7 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.
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).