| ARI | Aberdeen (Scotland) Royal Infirmary 
| Others |
| ARI | Aberdeen Royal Infirmary
| Others |
| ARI | Accelerated Reading Instituteuction
| Others |
| ARI | Accelerated Reading Instruction
| Others |
| ARI | Accelerated Research Initiative
| Others |
| ARI | Activity Recommendation Information
| Others |
| ARI | Acute Respiratory Infection
| Others |
| ARI | Address Recognized Indicator
| Others |
| ARI | Addressee Routing Indicator
| Others |
| ARI | Adjusted Rand Index
| Others |
| ARI | Advancing Recovery in Ireland
| Others |
| ARI | Africa Research Institute
| Others |
| ARI | Agricultural Research Institute
| Others |
| ARI | AIDS Research Institute
| Others |
| ARI | Air-Conditioning and Refrigeration Institute
| Others |
| ARI | Alabama Reading Initiative
| Others |
| ARI | Alarm Relay Interface
| Others |
| ARI | Alcohol-Related Incidents
| Others |
| ARI | ALIREAZ INC
| Others |
| ARI | Alpaca Registry Inc
| Others |
| ARI | Alpaca Registry, Inc.
| Others |
| ARI | Always Reaching for Independence
| Others |
| ARI | American Remanufacturers, Inc.
| Others |
| ARI | Analytic Reading Inventory
| Others |
| ARI | Animal Research Institute
| Others |
| ARI | Anxiety Reaction, Intense
| Others |
| ARI | Application, Resume, and Interview
| Others |
| ARI | Application, Resume, Interview
| Others |
| ARI | ARI Compressed file archive
| Others |
| ARI | Arica, Chile
| Others |
| ARI | Aristotle
| Others |
| ARI | Aristotle Audio file
| Others |
| ARI | Arizona Cardinals
| Others |
| ARI | Arizona Diamondbacks
| Others |
| ARI | Army Research Institute (for behavioral and social sciences)
| Others |
| ARI | Asia Research Institute
| Others |
| ARI | Asian Relief, Inc.
| Others |
| ARI | Aslag Research Institute
| Others |
| ARI | Aspect Ratio Information
| Others |
| ARI | Associazione Radioamatori Italiani
| Others |
| ARI | Asterisk REST Interface
| Others |
| ARI | Augmented Reality Interface
| Others |
| ARI | Aurora Research Institute
| Others |
| ARI | Autism Research Institute
| Others |
| ARI | Auto Radio Information
| Others |
| ARI | Auto Repair Invoices
| Others |
| ARI | Autofahrer Rundfunk Information
| Others |
| ARI | Automated Readability Index
| Communication, Language |
| ARI | Automated Research Inc
| Others |
| ARI | Automated Reset Indication
| Others |
| ARI | Automatic Return Item
| Others |
| ARI | Automatic Room Identification
| Others |
| ARI | Automotive Recyclers of Indiana
| Others |
| ARI | Automotive Repairs Inc.
| Others |
| ARI | Automotive Research Institute
| Others |
| ARI | Automotive Resources Inc.
| Others |
| ARI | Automotive Resources International
| Others |
| ARI | Automotive Robotics Inc.
| Others |
| ARI | Automotive Robotics India
| Others |
| ARI | Average Recurrence Interval
| Others |
| ARI | Ayn Rand Institute
| Others |
| ARI | Dodge Aries
| Others |