| Acronym | Definition |
|---|
| ARU | Australian Rugby Union |
| ARU | Architecture Research Unit (London Metropolitan University; UK) |
| ARU | Alarm Relay Unit |
| ARU | Automatic Response Unit |
| ARU | Anglia Ruskin University (Cambridge and Chelmsford, UK) |
| ARU | Audio Response Unit |
| ARU | Aquarium Rescue Unit (band) |
| ARU | American Railway Union (est. 1893) |
| ARU | Asociacion Rural del Uruguay (Spanish: Rural Association of Uruguay) |
| ARU | Ardhi University (Tanzania) |
| ARU | Automated Response Unit |
| ARU | Applied Research Unit (various organizations) |
| ARU | Acute Rehabilitation Unit |
| ARU | Air Removal Unit |
| ARU | Australian Railways Union (Victoria, Australia) |
| ARU | Appropriate Resource Use (healthcare) |
| ARU | Armed Response Unit (UK police) |
| ARU | Arizona Regents University (Arizona State University, Northern Arizona University, and University of Arizona joint distance learning program) |
| ARU | Affect, Reason, Utility (neural network models) |
| ARU | Alumni Relations Unit (Asian Institute of Technology) |
| ARU | Alarm Relay Unit (Cisco) |
| ARU | Attitude Reference Unit |
| ARU | Aural Resuscitation Unit (band; Dubuque, IA) |
| ARU | Asbestos Reporting Unit |
| ARU | Antenna Remote Unit |
| ARU | Acid Recovery Unit |
| ARU | Address Recognition Unit |
| ARU | Automatic Release Update (Oracle) |
| ARU | USIGS Architecture Division (NIMA) |
| ARU | Access/Relay Unit |
| ARU | Acknowledge Receipt & Understanding |
| ARU | Analog Routing Unit |
| ARU | American Research Union |
| ARU | Automated Release Upgrade (AT&T) |
| ARU | Acoustic Recording Unit |
| ARU | Association Roller Urbain (French: Urban Roller Association) |
| ARU | Automatic Resync Unit |