| AR | Arabic | |
| AR | Administrative Record | |
| AR | Argentina | |
|
| AR | Army Regulation | |
| AR | Amateur Radio | |
| AR | Annual Report | |
| AR | Accelerated Reader | |
| A/R | As Required | |
| AR | Adventure Racing | |
| AR | Animal Rights | |
| AR | Army Reserve | |
| AR | Arkansas (US postal abbreviation) | |
| AR | As Required | |
|
| AR | Annual Reviews | |
| AR | Action Required | |
| AR | American Revolution | |
| AR | Action Replay (game console cheat device) | |
| AR | Active Region (sunspot observation) | |
| AR | American Racing (American Racing wheels) | |
| AR | Assault Rifle | |
| AR | Action Research | |
| AR | Air Rifle | |
| AR | Annual Rate | |
| AR | Access Router | |
| AR | Amazing Race (reality TV show) | |
| AR | Acrobat Reader (Adobe Systems) | |
| AR | Armor | |
| AR | Anti-Reflection | |
| AR | Automatic Rifle | |
| AR | Acid Reflux | |
| AR | Abuse Report (gaming, Second Life) | |
| AR | Augmented Reality | |
| AR | Anti-Reflective | |
| AR | Aspect Ratio | |
| AR | Acoustic Research (loudspeaker manufacturer) | |
| AR | Authorized Representative | |
| AR | Annual Return | |
| AR | After Rebate | |
| AR | Abbey Road (Beatles album/song) | |
| AR | Aromatic | |
| AR | Androgen Receptor | |
| AR | Argent (Heraldic White or Silver) | |
| AR | Argon | |
| AR | Action Report | |
| AR | Arizona Republic (newspaper) | |
| AR | Activity Reports | |
| AR | Antibiotic Resistance | |
| AR | Accounts Receivable | |
| AR | Account Representative (Sprint) | |
| A/R | Accounts Receivable | |
| AR | Adrenergic Receptor (protein) | |
| AR | Repair Ship | |
| AR | Aishwarya Rai (Indian actress) | |
| AR | Abnormal Returns | |
| AR | Ayn Rand (novelist and philosopher) | |
| AR | Authorized Reseller | |
| AR | Armalite (rifle company) | |
| AR | All Risks | |
| AR | Aerolíneas Argentinas | |
| AR | Association Rules | |
| AR | Atlantic Records (record label) | |
| AR | Administrative Regulation (various organizations) | |
| AR | Address Register | |
| AR | Autoregressive | |
| AR | Alternate Routing | |
| AR | Appenzell Außerrhoden (Swiss Half Canton) | |
| AR | ArmaLite Rifle (engineering company; Genesco, IL) | |
| AR | Assistant Referee (sports) | |
| AR | Allergic Rhinitis | |
| AR | Akademia Rolnicza (Polish: University of Agriculture) | |
| AR | As Removed (avionics) | |
| AR | Automated Reasoning | |
| AR | Alan Rickman (British actor) | |
| AR | Autosomal Recessive (genetics; recessive gene on one of the 23 pairs of autosomes) | |
| AR | Alternative Radio (public affairs program) | |
| AR | Assembleia da República (Portuguese parliament) | |
| AR | Arrêté Royal (French: Royal Decree; Belgium) | |
| AR | Adverse Reaction | |
| AR | Accusé de Réception (French: Acknowledgment of Receipt; mail) | |
| A/R | Andata e Ritorno (Italian: Forward and Backward/Out and Home/First and Last Half) | |
| AR | Artificial Respiration (aka artificial resuscitation) | |
| AR | Analyst Relations (various locations) | |
| AR | Antimicrobial Resistance | |
| AR | Atmospheric Research | |
| AR | Ancien Regime (gaming) | |
| AR | Adrenaline Rush (gaming; also an IMAX film) | |
| AR | Arsenide | |
| AR | Acknowledge Receipt | |
| AR | Air Route | |
| A/R | Area/Radius (geometry) | |
| AR | Area Record (sports) | |
| AR | Air Refueling | |
| AR | Army Ranger | |
| AR | Aortic Regurgitation (aortic insufficiency) | |
| AR | Anal Retentive | |
| AR | Air Resistance | |
| AR | Area Ratio | |
| AR | Arista Records (record label) | |
| AR | Attributable Risk | |
| AR | Appenzell Ausser-Rhoden (postcode, Switzerland) | |
| AR | Aldose Reductase | |
| AR | American Robin | |
| AR | Aerial Refueling | |
| AR | Acute Rejection | |
| AR | Angle Resolved | |
| AR | All Rail | |
| AR | Attrition Rate | |
| AR | Access Right | |
| AR | Abandon Rate | |
| AR | Arm's Reach | |
| AR | Arezzo, Toscana (Italian province) | |
| AR | Authorization Request | |
| AR | Anti-Radiation | |
| AR | Aqua Regia | |
| AR | Aerial Reconnaissance | |
| AR | Agency Resources | |
| AR | Arrest Report (law enforcement) | |
| AR | Attack Rating (Diablo II) | |
| AR | Acquisition Reform | |
| AR | Autonomous Republic | |
| AR | Access Rate | |
| AR | Assistant Registrar | |
| AR | Automatic Response | |
| AR | Area Representative | |
| AR | Avis de Réception (Canada Post) | |
| AR | Age Regression | |
| AR | African Rights | |
| AR | Anti-Radar | |
| AR | Atrophic Rhinitis (pig respiratory disease) | |
| AR | Axial Ratio | |
| AR | Ancestral Roots (genealogy) | |
| AR | Approval Request | |
| AR | Air Reconnaissance | |
| AR | Active Radar | |
| AR | Activity Ratio | |
| AR | Approximate Reasoning | |
| AR | Attack Release | |
| AR | Anton Rubinstein (classical pianist) | |
| A/R | Antireflection | |
| AR | Auto Redial | |
| AR | Analytical Reagent | |
| AR | Airborne Reconnaissance | |
| AR | Aftermath Records (record label) | |
| AR | Agent Report | |
| AR | Add Register | |
| AR | Abstellraum (German: storage room) | |
| AR | Acceptance Review | |
| AR | Asistencia Respiratoria | |
| AR | Acquisition Risk | |
| AR | Art Remains (online art gallery) | |
| AR | Affiliate Relations | |
| AR | Accounts Register | |
| AR | Acquiescence Ruling | |
| AR | Application Record | |
| AR | Automation Resources | |
| AR | Automatic Recall (Bellcore) | |
| AR | Acetal Resin | |
| AR | Arrezo (postcode, Italy) | |
| AR | Advanced Reactor | |
| AR | Acoustic Reflex | |
| AR | Associate Referee (various organizations) | |
| AR | Alarm Reaction | |
| AR | Administrative Requirement | |
| AR | Assessment Request | |
| AR | American Rifleman Magazine | |
| AR | Armor Rating (gaming, Asheron's Call 2) | |
| AR | Auxiliary Relay | |
| AR | Acquisition Request | |
| AR | Alabama Railroad | |
| AR | Alarm Report | |
| A/R | Accepted/Rejected | |
| AR | Approved Rejected | |
| AR | Air Revitalization | |
| AR | Asset Reconciliation | |
| AR | Anomaly Report | |
| AR | Application Requester | |
| AR | Artificial Resuscitation | |
| AR | Auburn Reporter (community newspaper) | |
| AR | Anti-Reflectance | |
| AR | Arise Records | |
| AR | Airworthiness Representative | |
| AR | Airborne Relay | |
| AR | Activity Resume (ITU-T) | |
| AR | American Rivers, Inc. | |
| AR | Advice of Receipt (Canada Post) | |
| AR | Absorber Rod | |
| AR | Acoustique Renforcée (French: Enhanced Acoustics; window noise insulation) | |
| AR | Auxiliary Room | |
| AR | Archival Researcher | |
| AR | Affirmative Rebuttal (debate) | |
| AR | Attrition Reserve (aircraft) | |
| AR | Postal Fiscal (Scott Catalogue prefix; philately) | |
| AR | Atmospheric Revitalization | |
| AR | Automatic Resupply | |
| AR | Auxiliary Receiver | |
| AR | Avance-Retard (French) | |
| A/R | Accept/Refuse (message) | |
| AR | Auscultacion Respiratoria (Spanish: Respiratory Auscultation) | |
| AR | Arrow Revolver (game, Mabinogi) | |
| AR | Attributive Risk | |