AR

AR, Ar, or A&R may refer to:

Arts, entertainment, and media

Music

• Artists and repertoire

Periodicals

• Absolute Return + Alpha, a hedge fund publication
• The Adelaide Review, an Australian arts magazine
• American Renaissance (magazine), a white nationalist magazine and website
• Architectural Review, a British architectural journal
• Armeerundschau, a magazine of the East German army

Other media

• Ar, city on the fictional planet Gor
• a.r. group of Polish artists and poets, including Katarzyna Kobro
• Parallel universes in fiction, various fictional concepts

Businesses

• Accounts receivable, abbreviated as AR or A/R
• Acoustic Research, an American audio electronics manufacturer
• Aerolíneas Argentinas (IATA airline code AR)
• Some Alfa Romeo car models, e.g. AR51
• Toyota AR engine

Mathematics, science, and technology

Computing

• ar (Unix), a Unix archive format and handling tool
• Accelerated Reader, educational reading assessment software
• Augmented reality, an application of virtual reality in the real world

Biology and medicine

• Androgen receptor, a nuclear hormone receptor
• Aortic regurgitation, a heart valve disease
• Autosomal recessive inheritance

Mathematics

• ar-, a prefix of inverse hyperbolic functions
• Autoregressive model, concerning random processes in statistics

Physics and chemistry

• Aqua regia, a chemical mixture
• Archimedes number in fluid dynamics
• Argon, a chemical element with symbol Ar
• Aryl group in organic chemistry
• Relative atomic mass, symbolized as A_r

Other uses in mathematics, science, and technology

• Anti-reflective, coating of lenses
• Aspect ratio (aeronautics), of a wing

Military

• US Navy hull classification symbol for repair ships
• Army Reserve (Ireland), the land component of the Irish Reserve Defence Forces (RDF)

Places

• Ar (city), in ancient Moab
• Appenzell Outer Rhodes, Switzerland
• Province of Arezzo, Italy, vehicle registration code
• Argentina (ISO 3166-1 alpha-2 country code)
  • .ar, the country code Top Level Domain for Argentina
• Arkansas, United States
• Armstrong–Ringsted Community School District, Iowa, United States

Other uses

• Antipodean Resistance, an Australian neo-Nazi group
• Ar (cuneiform), a cuneiform combined sign
• Ar, the spelled-out name of the letter R
• 🜇 or AR, a numismatic abbreviation for "silver"
• Arabic, by ISO 639-1 language code
• Argent, the heraldic tincture of silver
• Armalite Rifle
• Assault rifle
• Assistant referee (association football)
• Auto rickshaw, a motorized three-wheeled vehicle common in South Asia
• Avis de réception, postal advice or acknowledgement of receipt