AR

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

Arts, entertainment, and media

Music

• Artists and repertoire
• AR (EP), the debut EP by Addison Rae

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, an avant-garde art group
• Alternate reality (disambiguation), various fictional concepts

Business

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

Language

• Ar, the Latin letter R when spelled out
• Ar (cuneiform), a cuneiform combined sign
• Arabic, by ISO 639-1 language code

Science and technology

Computing

• Accelerated Reader, educational reading assessment software
• Adaptive routing, in networking
• Adobe Aero, an Adobe software
• ar (Unix), a Unix archive format and handling tool
• 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, chemistry and engineering

• Anti-reflective, coating of lenses
• Aqua regia, a chemical mixture
• Archimedes number in fluid dynamics
• Argon (Ar), a chemical element
• Aryl group, in organic chemistry
• Aspect ratio (aeronautics), of a wing
• Relative atomic mass (A_r), the ratio of the average mass of atoms of an element

Military and weapons

• A US Navy hull classification symbol: Repair ship (AR)
• Armalite Rifle
  • AR-15–style rifle, rifles based on ArmaLite's AR-15
• Army Reserve (Ireland), the land component of the Irish Reserve Defence Forces (RDF)

Places

• Ar (city), in ancient Moab
• Appenzell Ausserrhoden, 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
• Arunachal Pradesh, a state of India

Politics and ethics

• Affirmative Repositioning, a political movement in Namibia
• Animal rights, a philosophy
• Animal rights movement, a social movement advocating for other animals
• Antipodean Resistance, an Australian neo-Nazi group

Other uses

• 🜇 or AR, a numismatic abbreviation for "silver"
• Argent, the heraldic tincture of silver
• Assistant referee (association football)
• Auto rickshaw, a motorized three-wheeled vehicle common in South Asia
• Avis de réception, postal advice or acknowledgement of receipt