| Abbreviation | Definition |
|---|---|
| NMOS | Negative channel Metal-Oxide Semiconductor |
| NMPM | Negative Magnetic Permeability Media |
| NMR | Noise Masking Ratio |
| NMR | Normal Mode Rejection |
| NMR | Nuclear Magnetic Resonance |
| NMWU | Non-Metallic Wet Underground |
| NN | Negative or Minus connection |
| NN | Neural Network |
| NNN | Next Nearest Neighbor |
| NO | Normally Open |
| NOB | Non-biased Optical Bistable (device) |
| NOC | Normally Open Contact |
| NOCI | Non-Orthogonal Configuration Interaction |
| NOEC | Northeast Oklahoma Electric Cooperative |
| NOEC | Northwest Oklahoma Electric Cooperative |
| NOES | Non Oriented Electrical Steels |
| NOLM | Non-linear Optical-fiber Loop Mirror |
| NOMF | Non-Operative Management with Failure |
| NOMV | Normally Open Master Valve |
| NOR | Not OR |