| Acronym | Definition |
|---|
| OCN | Operating Company Number (NANPA) |
| OCN | Osteocalcin (protein) |
| OCN | Oncology Certified Nurse |
| OCN | Orthodox Christian Network |
| OCN | Office of Child Nutrition |
| OCN | Oceanography |
| OCN | Optical Communications and Networking |
| OCN | Open College Network |
| OCN | Open Computer Network |
| OCN | Other Carrier Networks (Sprint) |
| OCN | Of Course Not |
| OCN | Original Called Number |
| OCN | Original Camera Negative (film) |
| OCN | Ontario College of Nurses (Ontario, Canada) |
| OCN | On-Chip Network |
| OCN | Orange County News Channel |
| OCN | Other Country National |
| OCN | Organized Crime Narcotics |
| OCN | Optimal Climate Normals (meteorology) |
| OCN | Original Cost New |
| OCN | Overclock.net (gaming) |
| OCN | Outpatient Care Network |
| OCN | Okinawa Cable Network (Okinawa, Japan) |
| OCN | Operational Control Node |
| OCN | Order Control Number |
| OCN | Optillingscondensatieniveau (Dutch: lifting condensation level) |
| OCN | Optical Carrier Level N |
| OCN | Operational Carrier Number |
| OCN | Open Communications Networks Inc. |
| OCN | Operations Control Number |
| OCN | Owning Company Number (LEC calling cards) |
| OCN | Office Control Number |
| OCN | Operational Company Number |
| OCN | Original Call Number |