AO

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

Places

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 movie
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

AO (originally American Optical Company) eyeglass lenses, a brand now merged with Carl Zeiss Vision
AO Foundation (originally Arbeitsgemeinschaft für Osteosynthesefragen), a non-profit organisation dedicated to the treatment of trauma and disorders of the musculoskeletal system
AO World, a UK retailer of household appliances trading under the brand name ao.com
Aktsionernoye Obschestvo or Aktsionernoye Obshchestvo (акционерное общество), 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)

.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.
Authorship obfuscation, a privacy technique

Alphabetically ordered
Ao (color)
Ao (digraph)
Ao languages
Ao Naga, an Indian ethnic group
ao or außerordentlicher, meaning extraordinary professor (academic rank in Germany)
Australian Open, an annual tennis tournament in Melbourne, Australia
A^o, an abbreviation of "Anno", meaning "In the year" (as in Anno Domini)
Te Ao Māori (literally "The Māori world"), Māori cultures and traditions