| Abbreviation | Definition |
|---|---|
| OMRSD | Operations and Maintenance Requirements and Specifications Document |
| OMS | Operations Management System |
| OMS | Orbital Maneuvering System |
| OMS | Orbital Maneuvering System (Subsystem) |
| OMSF | Office of Manned Space Flight |
| OMSF | Office of Manned Space Flight (now OSTS) |
| OMSP | Operational Maintenance Support Plan |
| OMU | Optical Measuring Unit |
| OMV | Orbital Maneuvering Vehicle |
| OMV | Oxygen Manual Valve |
| OMZ | Oxygen Minimum Zone |
| O-NAV | Onboard Navigation |
| ONBD | Onboard |
| ONBT | Orbiter Neutral Buoyancy Trainer |
| ONC | Optical Navigation Camera |
| OND | Operator Need Date |
| ONSTRN | Original Numbers Similar To Roman Numerals |
| OOD | Orbiter On-Dock |
| OODP | Out-of-Detent Pitch |
| OODR | Out-of-Detent Roll |