| Abbreviation | Definition |
|---|---|
| RHIC | Relativistic Heavy Ion Collider |
| RHQ | Regional Head Quarters |
| RHS | Rural Housing Service |
| RI | Reference Implementation |
| RIA | Research Institute of America |
| RIAC | Reliability Information Analysis Center |
| RIAT | Risk Intelligence and Analysis Team |
| RIC | Regional Intersectoral Committee |
| RICO | Regulated Industries Complaints Office |
| RID | Records Information Documentation |
| RIF | Reading Is Fundamental |
| RIGOR | Reference Internet Government Office Registrars |
| RII | Required Inspection Item |
| RIM | Regulatory Impact Model |
| RIP | Regulation Of Investigatory Powers |
| RIP | Remediation in Progress |
| RIPIA | Regulatory Impact Post-Implementation Assessment |
| RIPW | Remediation In Progress Waiver |
| RIR | Recordable Injury Rate |
| RIRIP | Risk-Informed Regulation Implementation Plan, by the Nuclear Regulatory Commission |