AO, aO, Ao, or ao may refer to:

Places

  • Ao (building)
  • Ao, Estonia, village in Väike-Maarja Parish, Lääne-Viru County, Estonia
  • Ao Line, commuter railway line in Hyōgo Prefecture, Japan
  • Ao River (Zhejiang) (鳌江), Zhejiang, China
  • Ao River (Fujian) (敖江), Fujian, China
  • Ao Station, railway station in the city of Ono, Hyōgo Prefecture, Japan
  • Aodu, capital of Shang dynasty, near Zhengzhou
  • Aoshima, Ehime, island in Japan
  • Aoshima, Miyazaki, island in Japan
  • Angola (ISO 3166-1 alpha-2 code AO)

Arts and entertainment

  • Adults Only, an entertainment rating
  • AO Music (AOmusic), a world-music fusion group consisting of Jay Oliver, Miriam Stockley and others
  • Ao: The Last Hunter, a 2010 prehistoric drama film
  • Eureka Seven: AO, Japanese mecha anime television series
  • Lord Ao, a fictional deity in the Dungeons & Dragons universe
  • Annoying Orange, an American comedy web series

Businesses and organizations

  • AO (originally American Optical Company) eyeglass lenses, a brand now merged with Carl Zeiss Vision
  • AO Foundation (originally ), a non-profit organisation dedicated to the treatment of trauma and disorders of the musculoskeletal system
  • AO Racing, an American sports car racing team
  • AO World, a UK retailer of household appliances trading under the brand name ao.com
  • AO, or (), a type of Russian corporate entity; see open joint-stock company
  • Athletics Ontario, formally Ontario Track and Field Association (OTAF)
  • Australian Airlines (IATA code AO)

Government and politics

  • Administrative Office of the United States Courts
  • Administrative Officer (United Kingdom), a grade within the United Kingdom's Civil Service
  • Administrative Officer (Hong Kong), a grade within the Hong Kong's Civil Service
  • Autonomous oblast, type of Russian administrative division
  • Autonomous okrug, type of Russian administrative division
  • NSDAP/AO, Foreign Organization branch of the Nazi Party
  • Officer of the Order of Australia, postnominal AO

Military

  • Area of operations, a U.S. military term
  • A US Navy hull classification symbol: Fleet oiler (AO)
  • AO-, the prefix for several firearms
  • Aviation Ordnanceman, a United States Navy occupational rating

Philosophy and religion

  • Alpha and Omega (abbreviation)
  • Ao (Māori mythology), a deity in Māori mythology
  • Ao (turtle), a creature in Chinese mythology
  • Ao, a type of Easter Island wood carving

Science and technology

  • (697402) Ao, a main-belt asteroid
  • .ao, top-level Internet domain code for Angola
  • Adaptive optics, an astronomical imaging technology
  • Ambient occlusion, a shading method in computer graphics
  • AMSAT-OSCAR, a satellite naming convention
  • Applied Optics, scientific journal published by the Optical Society of America (OSA)
  • Arctic oscillation, a climate pattern
  • Atomic orbital, in physics and chemistry
  • Ao, the atomic symbol for the misidentified chemical element Ausenium
  • Acridine orange, a fluorescent dye
  • Authorship obfuscation, a privacy technique

Surnames and initials

  • Ao (surname) (), a Chinese surname
  • Ou (surname) (/ and /), romanized as Ao in Cantonese
  • Ao Omae (born 1992), Japanese fiction writer
  • Aaron Owens (born 1976), American streetball player

Other uses

  • Alphabetically ordered
  • Ao (color)
  • Ao (digraph)
  • Ao Naga, an ethnic group in northeastern India
  • Ao language, a Tibeto-Burman (Sino-Tibetan) language spoken by the Ao Naga
  • Ao languages, a Sino-Tibetan language family of India
  • or , meaning extraordinary professor (academic rank in Germany)
  • Australian Open, an annual tennis tournament in Melbourne, Australia
  • A<sup></sup>, an abbreviation of "Anno", meaning "In the year" (as in Anno Domini)
  • Te Ao Māori (literally "The Māori world"), Māori cultures and traditions

See also

  • Alpha and Omega (disambiguation)
  • A0 (disambiguation)
  • Å, a letter derived from A with an O above or beside it.