| Abbreviation | Definition |
|---|---|
| OAM | Outcomes And Measurement |
| OAN | Objectively Assessed Need |
| OAN | Open All Night |
| OAN | Owner Applied Number |
| oao | on account of |
| OAP | On-line Action Plan |
| OAR | Owner's Authorized Representative |
| OARS | Opening Automated Report Service |
| OAS | Overpayments And Accounting Summary |
| OASIS | Olsen Assisting Students In Success |
| OASIS | Online Agency Sales Integrated System |
| OASIS | Online Automotive Service Information System |
| OASIS | Operational Application Support Information Services |
| OASIS | Outsourced Application Software and Information Services |
| OASIS | Outstanding Adults Still In Service |
| OATS | Obligations Assimilables du Trésor |
| OATS | Options Automated Trading System |
| OATS | Order Audit Trail System |
| OB | Official Business, 'NOT BUSINESS IN GENERAL ! ' |
| OB | Operating Budget |