| Abbreviation | Definition |
|---|---|
| NVMA | North Vancouver Museum and Archives |
| NVRM | National Voting Rights Museum |
| NWCM | National Watch and Clock Museum |
| NWM | National Waterways Museum |
| NWM | National Wool Museum |
| NYMMA | New York Metropolitan Museum of Art |
| NYMT | New York Museum of Transportation |
| NZP | National Zoological Park |
| OAI | Open Archive Initiative |
| OBRM | Oyster Bay Railroad Museum |
| OCM | Omaha Childrens Museum |
| OCM | Omaha Children's Museum |
| OCMA | Orange County Museum of Art |
| OCMA | Orniaorange County Museum Of Art |
| OCRHM | Ouray County Ranch History Museum |
| OERM | Orange Empire Railway Museum |
| OERM | Oregon Electric Railway Museum |
| OIM | Oriental Institute Museum |
| OIMP | Oriental Institute Museum Publications |
| OIMR | Optik Industrie Museum Rathenow |