| n | Nano (10^-9) |
| N | Negative |
| N | Nitrogen |
| N | Number of turns in an inductor |
| N | Revolutions per minute |
| NA | Numerical Aperture; Network Analyzer |
| NAA | Neutron activation analysis |
| NADC | North American Digital Cellular |
| NADCAP | National Aerospace and Defense Contractors Accreditation Procedures |
| NAMPS | Narrow band Advanced Mobile Phone Service |
| NASA | National Aeronautics and Space Administration |
| NAVSTAR | NAVigation Satellite Timing And Ranging |
| NBE | Near Band Edge |
| NBS | National Bureau of Standards |
| NC | NanoCrystal; Numerical control |
| NC | Network Computer |
| NC | No connection |
| NC | Normally closed |
| NCMS | National Center for Manufacturing and Science |
| NCS | Network Communication Standard |
| NCTA | National Cable & Telecommunications Association |
| ND | New Donor; Native defect |
| NDE | Nondestructive evaluation |
| NDIR | Non-dispersive infrared spectroscopy |
| NDT | NonDestructive Testing |
| NDUV | Non-Dispersive UltraViolet spectroscopy |
| NEC | National Electric Code |
| NECQ | National Electronics Component Qualification System |
| NEMA | National Electrical Manufacturers Association |
| NEP | Noise Equivalent Power |
| NESHAP | National emissions standards for hazardous air pollutants |
| NETD | Noise Equivalent Temperature Difference |
| NEXAFS | Near Edge X-ray Absorption Fine Structure |
| NEXT | Near End CrossTalk |
| NF | Noise Figure |
| NFE | Near Free Electron |
| NFM | Noise Figure Meter |
| NFOM | Near field optical microscopy |
| NFPA | National Fire Protection Association |
| NGT | Not Greater Than |
| NIC | Network Interface Card |
| NIH | National Institutes of Health |
| NIP | N-type/Intrinsic/P-type |
| NIST | National Institute for Science and Technology |
| NITF | News Industry Text Format |
| NIU | Network Interface Unit |
| NLO | Non-Linear Optic |
| NLR | Non-Linear Refraction |
| NLT | Not Less Than |
| NMOS | Negative channel metal-oxide semiconductor |
| NMR | Nuclear Magnetic Resonance; Normal mode rejection |
| NN | Nearest Neighbor; Neural network |
| NNN | Next Nearest Neighbor |
| NO | Normally open |
| NOB | Non-biased Optical Bistable (device) |
| NOCI | Non Orthogonal Configuration Interaction |
| NPL | Zero (No) Phonon Line |
| NPN | Negative-positive-negative |
| NPR | Noise Power Ratio |
| NPT | Non-Punch Through |
| NPV | Net Present Value |
| NR | Noise Reduction |
| NRA | Nuclear Reaction Analysis |
| NRE | Non-Recurring Engineering |
| NRZ | Non-Return to Zero |
| NSA | National Secutity Agency |
| NSE | Neutral Stream Etch |
| NSF | National Science Foundation |
| NSP | Native Signal Processing |
| NTC | Negative Temperature Co-efficient |
| NTD | Neutron Transmutation Doping |
| NTE | Not To Exceed |
| NTP | Normal Temperature and Pressure |
| NTSC | National Television System Committee |
| NTU | Network Terminal Unit |
| NV | Non-Volatile |
| NVM | Non-Volatile Memory |
| NVR | Non-Volatile Residue |
| NVRAM | Non Volatile Random AccessMemory |
| NVRAM | Non-Volatile RAM |
| NVoD | Near Video On Demand |
| Na | Sodium |
| nA | Nanoampere |
| NAND | Logic term NOT-AND |
| Ne | Neon |
| NEG, neg | Negative |
| NewsML | News Mark-up Language |
| NexGeRad | Next Generation Radar (Doppler Radar) |
| nF | Nanofarad |
| nH | Nanohenry |
| nm | Nanometer |
| NOR | Logic term NOT-OR |
| NOT | Logic term NOT |
| ns | Nanosecond |
| nW | Nanowatt |
