| Abbreviation | Definition |
|---|---|
| OMRF | Orbiter Modification and Refurbishment Facility |
| OMRP | Operations and Maintenance Requirements Plan |
| OMRS | Operations and Maintenance Requirements Specification |
| OMRSD | Operations and Maintenance Requirements and Specifications Document |
| OMRSD | Operational Maintainability Reporting Systems Document |
| OMRSD | O&M Requirements and Specification Documentation |
| OMS | Output per Man Shift |
| OMS | Orbital Maneuvering System (Subsystem) |
| OMS | Operations Management System |
| OMS | Orbital Maneuvering System |
| OMSF | Office of Manned Space Flight (now OSTS) |
| OMSP | Operational Maintenance Support Plan |
| OMT | Orthopaedic Manipulative Physiotherapist |
| OMU | Optical Measuring Unit |
| OMV | Oxygen Manual Valve |
| OMV | Orbital Maneuvering Vehicle |
| OMZ | Oxygen Minimum Zone |
| ON | Operational Navigation |
| ONB | Olfactory Neuroblastoma |
| ONBD | Orbiter Neutral Buoyancy Trainer |
| ONBT | Office of Naval Research |
| ONC | Orbiter On-Dock |
| OND | Journal of Aerospace Science |
| OND | Out-of-Detent Pitch |
| ONE | Over Nearly Everyone |
| ONER | Oceanic Navigational Error Report |
| ONG | Optic Nerve Glioma |
| ONGC | Oil & Natural Gas Commission |
| ONGS | Oil and Natural Gas Commission |
| ONICRA | Onida Individual Credit Rating Agency of India |
| ONR | Out-of-Detent Roll |
| ONR | Office of Naval Research |
| ONS | Office of National Statistics |
| ONU | Organizaci |
| ONU | Organizzazione delle Nazioni Unite |
| OOAS | West African Health Organization |
| OOBE | Out - Of - Box Experience |
| OOD | Organizational Operations and Maintenance Manual |
| OODP | Out of Position |
| OODR | Out Of Plane Spectrometer |
| OOH | Occupational Outlook Handbook |
| OOMM | Orbit-to-Orbit Stage |
| OOP | Ordinary Object Pointer |
| OOP | Orbit-to-Orbit Shuttle |
| OOP | Object-Oriented Programming |
| OOPS | On-Orbit Station |
| OOR | Occupational Outlook Report |
| OOS | On-Orbit Station Distribution Panel |
| OP | Official Photographer |
| OPA | Overseas Performing Artist |