| Abbreviation | Definition |
|---|---|
| NOM | National Offender Management |
| NOMS | National Offender Management Service |
| NP | Not Pertinent |
| NPC | Newspaper clippings |
| NR | No Record |
| NRO | National Reconnaissance Office |
| NS | Northern Structure |
| NSA | National Security Agency |
| NSC | National Security Council |
| NSCP | National Soil Conservation Program |
| NSL | National Security Letter |
| NY | New York Field Office |
| NYPD | New York Police Department |
| O | Office |
| O&C | Official and Confidential |
| OBL | Osama Bin Laden |
| OC | Out of the Country |
| OCCB | Organized Crime Control Bureau |
| ODALE | Office of Drug Abuse Law Enforcement |
| ODC | Other Direct Charges |