| Abbreviation | Definition |
|---|---|
| OPCC | Opinion of Probable Construction Cost |
| OPCEA | Ontario Pollution Control Equipment Association |
| OPE | Outdoor Power Equipment |
| OPIA | Ontario Plumbing Inspectors Association |
| OPSD | Ontario Provincial Standard Drawing |
| OPSS | Ontario Provincial Standard Specification |
| OPTC | Ontario Pipe Trades Council |
| OREL | Overload Relay Elevator Loading |
| ORG | Overflow Relief Gully |
| ORMC | Offshore Reliability Maintenance and Construction |
| ORSA | Orbit Reconstruction Simulation and Analysis |
| OSA | on-site assem bly |
| OSCC | Off Site Construction Council |
| OSCR | On Site Construction Robot |
| OSCV | Offshore Subsea Construction Vessel |
| OSCV | Offshore Subsea Construction Vessels |
| OSCV | offshore support and construction vessel |
| OSDS | On-Site Disposal System |
| OSHA | Occupational Safety and Health Administration |
| OSM&AHG | Ontario Sheet Metal Air Handling Group |