| Technology Archive Reference - O |
| ODAPI | Open Data API (revised as IDAPI - Borland Database Engine) |
| ODI | Open Data-Link Interface (networking API developed by Apple and Novell) |
| ODMA | Open Document Management API |
| OME | Open Messaging Environment |
| OPM | Operations Per Minute |
| OPS | Operations Per Second |
| OSA | Optical Society of America (known as Optica) |
| OWL | Object Windows Library (Borland) |
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