1. Arts, entertainment, and media
    Music  Periodicals  Other media 

2. Businesses

3. Firearms

4. Language

5. Mathematics, science, and technology
    Computing  Biology and medicine  Mathematics  Physics and chemistry  Other uses in mathematics, science, and technology 

6. Military

7. Places

8. Other uses

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

Arts, entertainment, and media

Music

• Artists and repertoire

Periodicals

• Absolute Return + Alpha, a hedge fund publication
• American Renaissance (magazine), a white nationalist magazine and website
• Architectural Review
• 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
• Alternate reality (disambiguation), various fictional concepts

Businesses

• A & R Sales, a defunct firearms manufacturer
• Aerolíneas Argentinas (IATA airline code AR)
• Some Alfa Romeo car models, e.g. AR51
• Acoustic Research, an American audio electronics manufacturer
• Toyota AR engine

Firearms

• AR-57
• ArmaLite AR-5
• ArmaLite AR-7
• ArmaLite AR-10
• ArmaLite AR-15
• ArmaLite AR-18
• ArmaLite AR-30
• ArmaLite AR-50
• Colt AR-15

Language

• Ár, written "ᛅ", a rune of the Younger Futhark alphabet
• Arabic language (ISO 639 alpha-2 language code AR)

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

Mathematics

• Prefix of inverse hyperbolic functions, e.g. arsinh id the inverse of sinh
• Autoregressive model, concerning random processes in statistics

Physics and chemistry

• Archimedes number in fluid dynamics
• Argon, symbol Ar
• [Ar], electron configuration of chemical element preceded by noble gas Argon; e.g. Cr = [Ar]4s¹3d⁵
• Placeholder for the Aryl group in organic chemistry
• A_r, Relative atomic mass of a chemical element
• Analytic Reagent, a purity grade for reagents and solvents for use in chemical laboratories
• Aqua regia

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

Other uses

• Argent, the heraldic tincture of silver
• Assistant referee (association football)
• Avis de réception, postal advice or acknowledgement of receipt

• African immigrants to Italy
• African immigrants to Lithuania
• African immigration to Puerto Rico
• African indeginous religions
• African Independence
• African Independence (FIlm)
• African Independence (film)
• African Independence Movements
• African Index Medicus
• African & Indian Ocean Internet Registry
• African indigenous religions
• African Initiated Church
• African initiated churches
• African Institute of Mathematical Sciences
• African Institute of Science and Technology (Arusha)
• African-Iranian
• African Iranian
• African Iranians
• African-Iranians
• Africanised honey bee
• Africanised Honey Bee
• African Islamic Center
• African Jacana
• African Jazz
• African jazz (disambiguation)