| Acronym | Definition |
|---|
| OOS | Out of Stock |
| OOS | Out Of Service (police dispatch) |
| OOS | Out of State |
| OOS | On Other Sites |
| OOS | Object Oriented Software |
| OOS | Out of Service |
| OOS | Out of System |
| OOS | Object Oriented Simulation |
| OOS | Object Oriented Specification |
| OOS | Object Oriented Storage |
| OOS | Offline Operating Simulator |
| OOS | Open Office Spreadsheet |
| OOS | Object Oriented System |
| OOS | Occupational Overuse Syndrome (repetitive stress injury) |
| OOS | Out Of Specification |
| OOS | Origin of Symmetry |
| OOS | Out of School |
| OOS | Oracle of Seasons (video game in Zelda series) |
| OOS | Out-Of-Sequence |
| OOS | Out of Sight |
| OOS | Order of Service (religious worship) |
| OOS | Object-Oriented Systems |
| OOS | Out of Style |
| OOS | Out of Scope |
| OOS | Online Operating System |
| OOS | Order of Selection |
| OOS | Object Oriented Specification (computing) |
| OOS | Orbicularis Oris Superior |
| OOS | On-Orbit Servicing |
| OOS | Out of Supply |
| OOS | Out of Shape |
| OOS | Out of Season |
| OOS | Off-Line Operating Simulator |
| OOS | Ohio Ornithological Society |
| OOS | Order of Sargeras (gaming guild) |
| OOS | Outside of Society (Macromedia Flash game development team) |
| OOS | Out of Synchronization |
| OOS | Out of Straightness (pipeline condition leading to buckling) |
| OOS | On-Orbit Operations Summary |
| OOS | Online Order Status |
| OOS | Offshore Outsourced Services |
| OOS | Ohio Odonata Society |
| OOS | Orbit to Orbit Shuttle |
| OOS | Ottawa Orchid Society (Canada) |
| OOS | Oxfam Online Shop |
| OOS | Out of Square |
| OOS | Oregon Orchid Society (Portland, OR) |
| OOS | Online Ordering Service |
| OOS | Office Operations Supervisor (US Census Bureau) |
| OOS | Opportunity of Selection |
| OOS | OneSAF (One Semi-Automated Force) Objective System (OneSAF is an Army simulation) |
| OOS | Optical Output Synchronizer |
| OOS | Orbitto-Orbit Stage |