Tau (Τ or τ) is the 19th letter of the Greek alphabet.

Tau may also refer to:

Mathematics

• Tau (mathematics), a circle constant equal to (6.28318...)

• Tau test in statistics (tau-a, tau-b and tau-c tests or Kendall tau rank correlation coefficient)

• Tau function (disambiguation), several

Geography

• Tau, Norway, a small town in Strand municipality, Rogaland county, Norway

• Tău (disambiguation), two villages in Romania

• Ta‘ū, an island in the Manua Island Group of American Samoa

• Ta'u County, a county in American Samoa

• Tau (Tongatapu), an island of the Tongatapu group in Tonga

• Tau (Haapai), an island of the Haapai group in Tonga

• Tau (Botswana), a village at the base of the Tswapong Hills in Botswana

Science and technology

• TAU (spacecraft), a proposal to send a space probe to a thousand astronomical units from the Earth

• Tau (particle), also called Tau lepton, an elementary particle in particle physics

• Tau emerald, a species of dragonfly

• Tau neutrino a subatomic elementary particle

• Tau protein, a biochemical protein associated with microtubules

• Tau, the standard astronomical abbreviation for Taurus (constellation)

• Tau, a mutation in the Casein kinase 1 epsilon protein, in circadian biology

• Rational Tau, a UML and SysML modeling tool

• Opsanus tau, the scientific name for the oyster toadfish

Arts and media

• Tau (film), a 2018 thriller film starring Maika Monroe

• Tău (Negură Bunget album), a 2015 album by Romanian black metal band Negură Bunget

• T'au, an alien race from Warhammer 40,000

• Pan Tau, hero of Czech films and television series

• Tau Zero, a novel by Poul Anderson

• Tau Volantis, a planet shown in Dead Space 3

• Tau Cannon, an energy weapon from the video game Half-Life

• Tau Films, an American visual effects and animation company

• Tau, a stellar system mentioned in the video game Warframe

• Tau (sculpture), a sculpture by Tony Smith

Education

• Tama Art University

• Tel Aviv University

• Texila American University

• Anna University of Technology, Tiruchirappalli

People

• Abel Tau, South African politician

• Jimmy Tau, South African football (soccer) player

• Max Tau, German-Norwegian writer, editor, and publisher

• Nicolae Țâu, Moldovan politician who was Foreign Minister of Moldova between 1990 and 1993

• Parks Tau, South African politician who was mayor of Johannesburg from 2011-2016

• Percy Tau (born 1994), South African international footballer

• Tebogo Tau, Botswana judge

• Tau (rapper), Polish rapper

• Devi Lal (politician), popularly known as Tau, Indian politician who was Deputy Prime Minister from 1989 to 1991

Other

• Tau (mythology), an evil spirit in Guaraní mythology

• Tau effect, a sensory illusion relating to the perception of space

• Cross of Tau, a Christian symbol so called due to its resemblance to the letter Tau

• Tourist Association of Ukraine

• The Greek letter representing Expiration (options)

See also

• Tau function (disambiguation)

• Tao Chinese philosophy