| Abbreviation | Definition |
|---|---|
| RIOP | Rhode Island Organizing Project |
| RIOP | Rocks In Our Pockets |
| RIOP | Rural Idaho Outreach Partners |
| RIOP | Rural Idaho Outreach Program |
| RIOS | Reactive Infinite Order Sudden |
| RIOS | Realistic Imagination Of Success |
| RIOS | Recycling Industry Operating Standard |
| RIOS | Recycling Industry Operating Standards |
| RIOS | Resource Investment Optimization System |
| RIOS | Risk Issues Opportunities and Strengths |
| RIOS | Riverside Irvine Operating System |
| RIOT | Radical Image Optimization Tool |
| RIOT | Reaching In and Out Together |
| RIOT | Reaching Inside Out Tampa |
| RIOT | Recovery Is Out There |
| RIOT | Remote Interactive Optimization Testbed |
| RIOT | Revival In Our Teens |
| RIOT | Revolution in Our Time |
| RIOT | Righteous Invasion of Truth |
| RIOT | Rioting |