| Abbreviation | Definition |
|---|---|
| OGSA | Open Grid Service Architecture |
| OGSA | Open Grid Services Architecture |
| OGSF | Outside Gross Square Footage |
| OGSF | Overall Gross Square Feet |
| OHMA | Open Heterogeneous Multiprocessor Architecture |
| OHW | OverHead Weight |
| OIAM | Open Infrastructure Architecture method |
| OJ | Outer Join |
| OLA | Office for Local Architecture |
| OLA | Open Lighting Architecture |
| OLAD | Obligatory Layered Architecture Diagram |
| OMA | Office for Metropolitan Architecture |
| OMAC | Open Modular Architecture Control |
| OMAI | Open Mobile Architecture Initiative |
| ONA | Open Network Architecture |
| OOA | Office O Architects |
| OOAA | office of architectural affairs |
| OP | OPposite |
| OPA | Ogrydziak Prillinger Architects |
| OPA | Omni Path Architecture |