| ARU | Access/Relay Unit 
| Others |
| ARU | Acoustical Resistance Unit
| Others |
| ARU | Acute Rehabilitation Unit
| Others |
| ARU | Acute Retention Of Urine
| Others |
| ARU | African Rural University
| Others |
| ARU | Afromontane Research Unit
| Others |
| ARU | Air Removal Unit
| Others |
| ARU | Alarm Relay Unit
| Others |
| ARU | All Races United
| Others |
| ARU | All Received Up
| Others |
| ARU | All Rolled Up
| Others |
| ARU | Alternate Reality Universe
| Others |
| ARU | American Railway Union
| Others |
| ARU | Android Reconnaissance Unit
| Others |
| ARU | Aracatuba, Sao Paulo, Brazil
| Others |
| ARU | Architecture Research Unit
| Others |
| ARU | Army Rugby Union
| Others |
| ARU | Aspirin Reaction Unit
| Others |
| ARU | Audience Reference Unit
| Others |
| ARU | Audio Raid And Usb
| Others |
| ARU | Audio Response Unit
| Others |
| ARU | Australian Railways Union
| Others |
| ARU | Australian Rugby Union
| Others |
| ARU | Automated Response Unit
| Others |
| ARU | Automated Response Units
| Others |
| ARU | Automatic Release Update
| Others |
| ARU | Automatic Release Updates
| Others |
| ARU | Automatic Response Unit
| Others |
| ARU | Autonomous Recording Unit
| Others |
| ARU | Rural Association of Uruguay
| Others |