Au
Au, AU,  au or a.u. may refer to:

Science and technology
Computing
.au, the internet country code for Australia
Au file format, Sun Microsystems' audio format
Audio Units, a system level plug-in architecture from Apple Computer
Adobe Audition, a sound editor program
Windows Update or Automatic Updates, in Microsoft Windows
Windows 10 Anniversary Update, of August 2016a

Physics and chemistry
Gold, symbol Au (from Latin aurum), a chemical element
Absorbance unit, a reporting unit in spectroscopy
Atomic units, a system of units convenient for atomic physics and other fields
Ångström unit, a unit of length equal to 10−10 m or 0.1 nanometre.
Astronomical unit, a unit of length often used in planetary systems astronomy, an approximation for the average distance between the Earth and the Sun
Arbitrary unit, a relative placeholder unit for when the actual value of a measurement is unknown or unimportant ("a.u." is deprecated, use  "arb. unit" instead)

Arts and entertainment
Music
AU (band), an experimental pop group headed by Luke Wyland
Au, a 2010 release by Scottish rock band Donaldson, Moir and Paterson
Au a track on Some Time in New York City by an album by John Lennon & Yoko Ono and Elephant's Memory

Magazines
Alternative Ulster, a Northern Irish music magazine, now called AU
A&U: America's AIDS Magazine, sponsor of the Christopher Hewitt Award

Literature
Alternative universe (fan fiction), fiction by fan authors that deliberately alters facts of the canonical universe written about.

Other media
Au Co, a fairy in Vietnamese mythology
Age of Ultron, a 2013 series published by Marvel Comics
A.U, a Chinese media franchise and brand

Organizations
au (mobile phone company), a mobile phone operator in Japan
African Union, a continental union
Americans United for Separation of Church and State
Athletic Union, the union of sports clubs in a British university
Austral Líneas Aéreas (IATA code AU)
Auxiliary Units, specially trained, highly secret units created by the United Kingdom government during the Second World War

Universities
Asia
Ajou University  in Suwon, Gyeonggi, South Korea
Abasyn University in Peshawar, Khyber Pakhtunkhwa, Pakistan
Andhra University in Visakhapatnam, AP, India
Anhui University in Hefei, Anhui, China
Aletheia University in New Taipei City, Taiwan
Allahabad University in Allahabad, Uttar Pradesh, India
Arellano University in Philippines
Assumption University (Thailand) in Thailand
Abhilashi University in Himachal Pradesh, India
Adesh University in Bathinda, Punjab, India.

Europe
Aarhus University in Aarhus, Denmark
Aberystwyth University in Aberystwyth, Wales, United Kingdom
Akademia Umiejętności in Kraków, Poland
Arden University in Coventry, England

Oceania
Auckland University in New Zealand

North America
Adelphi University in Garden City, New York
Alfred University in Alfred, New York
Algoma University in Sault Ste. Marie, Ontario, Canada
American University in Washington, D.C.
Anaheim University in Anaheim, California
Anderson University (Indiana) in Anderson, Indiana
Anderson University (South Carolina) in Anderson, South Carolina
Andrews University in Berrien Springs, Michigan
Antioch University in Culver City, California
Apollos University in Huntington Beach, California
Arcadia University in Glenside, Pennsylvania
Argosy University in Alameda, California
Arizona University in Tucson, Arizona
Ashland University in Ashland, Ohio
Athabasca University in Athabasca, Alberta, Canada
Auburn University in Auburn, Alabama
Augsburg University in Minneapolis, Minnesota
Aurora University in Aurora, Illinois

Other
Air University (disambiguation), various Air Force universities

Places
Aue (toponymy), a frequent element in Germanic toponymy
Australia (ISO 3166 country code)
Au, Guinea, Kankan Region

Austria
Austria (informal two-letter country code)
Au, Vorarlberg, Bregenz, Austria
Au am Leithaberge, Austria
Au im Bregenzerwald, Austria

Germany
Au (Munich), Munich, Germany
Au (Schwarzwald), Baden-Württemberg, Germany
Au (squat), a building and cultural center in Frankfurt, Germany
Au am Rhein, Germany
Au in der Hallertau, Germany

Switzerland
Au, St. Gallen
Au, Zürich
Au peninsula
Schloss Au, a château in Wädenswil

Vehicles
Ford Falcon (AU), a family car made in Australia
Vought AU, a post-World War II US Marine Corps variant of the F4U Corsair aircraft

Other uses
Aú, a cartwheel in the Brazilian martial art of Capoeira
Au (surname), a Chinese family name
Au language
Ab urbe condita (sometimes abbreviated as a.u.), Latin for "from the founding of the City" (Rome)
a'u, the Hawaiian name for the Pacific blue marlin