| Acronym | Meaning |
 | OMDR | Operations And Maintenance Data Record |
 | OMDRI | Operations And Maintainability Data Record |
 | OME | Orbital Main Engine |
 | OMET | Orbiter Mission Elapsed Time |
 | OMEWG | Orbiter Maintenance Engineering Working Group |
 | OMI | Operations And Maintenance Instruction |
 | OMIS | Operational Management Information System |
 | OMISS | Operation And Maintenance Instruction Summary Sheet(s) |
 | OML | Orbiter Mold Line |
 | OML | Outer Mold Line |
 | OML | Outside Mold Line |
 | OMMH | Orbiter Maintenance Man-Hours |
 | OMNI | Omnidirectional |
 | OMNI | Omni-Range |
 | OMP | Operations And Maintenance Plan |
 | OMPR | Operational Maintainability Problem Reporting |
 | OMPT | Observed Mass Point Trajectory |
 | OMR | Operations And Maintenance Requirements |
 | OMR | Operations Management Room |
 | OMR | Orbiter Management Review |
 | OMRB | Operating Material Review Board |
 | OMRC | Operational Maintenance Requirements Catalog |
 | OMRF | Orbiter Modification And Refurbishment Facility |
 | OMRP | Operations And Maintenance Requirements Plan |
 | OMRSD | Document |
 | OMRSD | O&M Requirements And Specifications Documentation |
 | OMRSD | Operational Maintainability Reporting Systems Document |
 | OMRSD | Operational Maintenance Requirements And Specification |
 | OMS | Orbital Maneuvering Subsystem |
 | OMS | Orbital Maneuvering System |
 | OMSF | Office Of Manned Space Flight (now OSTS) |
 | OMSP | Operational Maintenance Support Plan |
 | OMU | Optical Measuring Unit |
 | OMV | Oxygen Manual Valve |
 | ONBD | Onboard |
 | ONBT | Orbiter Neutral Buoyancy Trainer |
 | OND | Operator Need Date |
 | ONR | Office Of Naval Research |
 | OOD | OrbiterOn-Dock |
 | OODP | Out-of-Detent Pitch |
 | OODR | Out-of-Detent Roll |
 | OOMM | Organizational Operations And Maintenance Manual |
 | OOP | Out Of Position |
 | OOS | On-Orbit Station |
 | OOS | Orbit-to-Orbit Shuttle |
 | OOS | Orbit-to-Orbit Stage |
 | OOSDP | On-Orbit Station Distribution Panel |
 | OOT | Out Of Tolerance |
 | OP | Open |
 | OP | Operate |