| Abbreviation | Definition |
|---|---|
| RIO | Reconfigurable Input Output |
| RIO | Reflective Interpolated Optical |
| RIO | Relation Inherited Object |
| RIO | Relational Intentional Overflow |
| RIO | Reliable Innovative and Outstanding |
| RIO | Ressoruces Input Optimisation |
| RIO | Restoration International Outreach |
| RIO | Restore Iraqi Oil |
| RIO | Review International Organization |
| RIO | Rigor in Operations |
| RIO | Rigour In Operations |
| RIO | Road Intersection Optimization |
| RIO | Robot Item Organizer |
| RIO | Rowing the Indian Ocean |
| RIOB | Redeploy Illinois Oversight Board |
| RIOLERING | Rioleringen |
| RIOM | Remote I O Module |
| RIOP | Radiation induced organizing pneumonia |
| RIOP | Research Integrity and Oversight Programs |
| RIOP | Revised Interim Operations Plan |