| Abbreviation | Definition |
|---|---|
| OPSF | Orthogonal Polynomials and Special Functions |
| OR | Odds Ratio |
| OR(s) | odds ratio(s) |
| OSC | Object Singleton Class |
| OSCAR | Ohio State Catalog of Automated Retrieval |
| OSF | Optimal Solutions Found |
| OSME | Origami in Science Mathematics and Education |
| OSMS | Outstanding Senior in Mathematics and Science |
| OSUM | Ohio State University Mathematics |
| OT | Other Terms |
| OTO | One To One |
| OTP | One Tree Point |
| OTP | Origin Template Plot |
| OTS | Outside The Square |
| OTTFF | One Two Three Four Five |
| OV | Optimal Value |
| OV | Output Variable |
| P | Parallel |
| P | Polynomial |
| P | Prime |