| Abbreviation | Definition |
|---|---|
| NWSP | North West Shelf Project |
| NWT | New With Tags |
| NWT | Noise When Tapped |
| NYS | Not Yet Started |
| NZE | Net Zero Energy |
| O&G | Oil and Grease |
| O&M | Operations & Maintenance |
| O&M | Operations and Maintenance |
| O/M | Operations and Maintenance |
| OAC | Action Construction |
| OAC | Official Acceptance of Construction |
| OAC | Owner-Architect-Contractor Meetings |
| OAC | Owner-Architect-Contractor Meetings |
| OACM | Owner Architect Construction Manager |
| OBC | Ontario Building Code |
| OBDC | Ontario Bid Depository Council |
| OBSROV | Observation class Remotely Operated Vehicle |
| OC | Oversite Concrete |
| OCA | Ottawa Construction Association |
| OCCA | Offsite Contemporary Construction for Accommodation |