| Abbreviation | Definition |
|---|---|
| OPSD | Organizational Preparedness for Secure Development |
| OPSM | Oracle Pedigree and Serialization Manager |
| OPSS | Orange Programmable Sensor System |
| OpSys | Operating System |
| optTune | Optimization Tuning |
| OR | logical OR (programming) |
| ORACLE | Oak Ridge Automated Computer And Logical Engine |
| ORACLE | Oak Ridge Automatic Computation Logical Engine |
| ORC | Oil Runtime Compiler |
| ORC | Online Roleplaying Client |
| ORCA | One Really Cool Application |
| ORCA | Open Resort Of Computer Applications |
| OrCAD | Oregon + CAD |
| ORCC | Open RVC CAL Compiler |
| ORE | Online Rpg Engine |
| ORL | Object Relational Language |
| ORP | OpenRISC Reference Platform |
| ORT | Operational Readiness Testing |
| OS | Open Sockets |
| OS | Open Source |