| Abbreviation | Definition |
|---|---|
| OR(s) | Odds ratio(s) |
| ORA | Operational Requirements Analysis |
| ORB | Officer Record Brief |
| ORB | Offworld Resource Base |
| ORBAT | Order of Battle |
| ORC | Organized Reserve Corps |
| ORCHIDEE | Observatoire radar coherent heliported'investi- gation des elements enemis |
| ORCON | Originator Controlled |
| ORD | Operational Requirements Document |
| ORD | Ordnance |
| ORDA | Open Radar Data Acquisition |
| ORDP | United States Army ORDnance Corps Pamphlet |
| ORDP | USAF Officer Recruiting Diversity Program |
| ORDREF | Order Reference |
| ORDTYP | Order Type |
| ORE | Operational Readiness Evaluation |
| ORF | Operational Readiness Float |
| ORG | Operations Research Group |
| ORG | Origin |
| ORG | Origin (GEOLOC) |