Term | Explanation |
| Nazi | An abbreviation for National Sozialistiche Deutsche Arbeitpartei the NSDAP, literally translated means National Socialist German Workers Party. |
| Neptune | Operational code name for the Allied D-Day Normandy beach landings - the assault phase of Operation Overlord. |
| Nest Egg | Operational code name for the British re-occupation of the Channel Islands - May 1945. |
| NID | Naval Intelligence Division. |
| NKVD | Narodni Komissarat Vnutrennykh Del - Soviet People's Comissariat of Internal Affairs - the predecessor to the KGB, the Soviet internal security organisation. |
| Noball | Operational code name for Allied air attacks on German V-weapons sites in 1944. |
| Nordlight | Northern Lights - Operational code name for the German attack on Leningrad in 1942. |
| Nordwind | North Wind - Operational code name for the German offensive in the Alsace - Winter 1944/45. |