| nnf | Cytoscape Nested Network Format File |
| nni | ANNI Neural Network Investing |
| nnl | Network Notepad Professional License |
| nnn | Filmetrics F20 Material Data |
| nnp | ANNI Neural Network Portfolio |
| nnr | NeuralWare NeuralWorks Data |
| nns | NobleNet Sealer File |
| nnt | Eudora Addressbook Database |
| nob | Chart Navigator Pro Navigation Objects Data |
| nod | MSC Patran Nodal Results |
| nom | PC-DMIS NOM File |
| nop | Nikon Optional Picture Control |
| nopd | Navicat for Oracle Data Synchronization Profile Data |
| nops | Navicat for Oracle Structure Synchronization Data |
| not | Adobe InCopy User Dictionary |
| not | Zemax Element Drawing Note |
| not | MakeMusic Finale Note File |
| notx | E-Sword v9 Study Note |
| notz | FiiNote Exported Note |
| nou | Numerical Electromagnetics Code Output |
| nov | Native Instruments Battery Data |
| nox | Wave IRIS NOx Data |
| noy | NOY Backup Data |
| np2 | Nikon Picture Control v2 Data |
| np3 | NP3 Compressed Nucleotide Database |
| npc | Intuit QuickBooks Online Banking Data |
| npg | Magentic Data |
| npk | MikroTik Router OS Upgrade Package |
| npo | Nonpareil Redundancy Summary Output |
| nps | NTI Backup Now Partition Set |
