| NEXT | Near End CrossTalk | In English | → Telecommunications |
| NFS | Nordisk Flagselskab (www.nordicflagsociety.org) = NFS | Nordisk Flaggselskap | In Norwegian = NFS | Nordic Flag Society | In English = NFS | Pohjoismaiden Lippuseura | In Finnish = NFS | Norræna Fánafélagið | In Icelandic = NFS | Nordiska Flaggsällskapet | In Swedish |
In Danish | → Organizations and associations → 6299 |
| NFS | Nordiska Flaggsällskapet (www.nordicflagsociety.org) = (look above) |
In Swedish | → Organizations and associations → 6299 |
| NFS | Nordic Flag Society (www.nordicflagsociety.org) = (look above) |
In English | → Organizations and associations → 6299 |
| NFS | Pohjoismaiden Lippuseura (www.nordicflagsociety.org) = (look above) |
In Finnish | → Organizations and associations → 6299 |
| NFS | Norræna Fánafélagið (www.nordicflagsociety.org) = (look above) |
In Icelandic | → Organizations and associations → 6299 |
| NFS | Nordisk Flaggselskap (www.nordicflagsociety.org) = (look above) |
In Norwegian | → Organizations and associations → 6299 |
| NFS | NASA FAR Supplement | In English | → Spaceflight engineering, astronautics |
| NGA | National Geospatial-Intelligence Agency | In English | → Central administration → Spaceflight engineering, astronautics |
| NGF | Nerve Growth Factor | In English | → Hormones → Neurology" |
| NGFAW | Nachrichtentechnische Gesellschaft Fachtagung über Antennen | In German | → Serial publications, periodicals → Telecommunications |
| NGT | NASA Ground Terminal | In English | → Spaceflight engineering, astronautics |
| NH&S | Nuclear Hardening and Survivability | In English | → Nuclear technology |
| NHB | NASA Handbook | In English | → Spaceflight engineering, astronautics |
| NHF | National Hemophilia Foundation | In English | → Foundations → Blood and circulatory system → Pathology |
| NHLBI | National Heart, Lung, and Blood Institute (www.nhlbi.nih.gov) | In English | → Research institutes → Blood and circulatory system → Cardiology → Medicine |
| NHTSA | National Highway Traffic Safety Association | In English | → Associations → Transport and postal services |
| NHTSA | National Highway Traffic Safety Administration (www.nhtsa.dot.gov) | In English | → Central administration → Transport and postal services |
| NHWA | National Highway Administration | In English | → Central administration → Transport and postal services |
| NIAS | National Institute of Advanced Studies | In English | → Mathematics and natural sciences |
| NICE | National Institute for Health and Clinical Excellence | In English | → Medicine |
| NICE | Nizhny Novgorod Innovation Center for Energy Saving | In English | → Energy economics |
| NIDDK | National Institute of Diabetes and Digestive and Kidney Diseases | In English | → Research institutes → Physiology → Pathology |
| NIFES | National Industrial Fuel Efficiency Service | In English | → Energy economics → Vehicle engineering |
| NIFO | Neidentigita Fluganta Objekto = OVNI | Objet Volant Non Identifié | In French = OVNI | Objecte Volador No Identificat | In Catalan = НЛО | Неидентифициран летящ обект | In Bulgarian = OVNI | Objeto Volador No Identificado | In Spanish = UFO | Unidentifiziertes Flugobjekt | In German = UFO | Unidentified Flying Object | In English = UFO | Unknown Flying Object | In English = UFO | Uidentificeret flyvende objekt | In Danish = UFO | Unbekend fleanend objekt | In Frisian = עב"מ | עצם בלתי מזוהה | In Hebrew = OVNI | Oggetto Volante Non Identificato | In Italian = NLO | Neidentificēts lidojošs objekts | In Latvian = UFO | Uidentifisert flygende objekt | In Norwegian = UFO | Uidentifisert flygande objekt | In Nynorsk = NOL | Niezidentyfikowany Obiekt Latający | In Polish = OVNI | Objeto Voador Não Identificado | In Portuguese = OZN | Obiect Zburător Neidentificat | In Romanian = НЛО | Неопознанный летающий объект | In Russian = NLO | Neidentifikovani leteći objekat | In Serbo-Croatian |
In Esperanto | → Spaceflight engineering, astronautics |
| NIFS | National Institute for Fusion Science | In English | → Research institutes → Nuclear, atomic, and molecular physics → Nuclear technology |
| NIFT | National Institute of Fashion Technology | In English | → Textile industry |
| NIFTE | National Initiative for Telehealth | In English | → Medicine |
| NIFTE | Non-Inertive Feedback Thermofluidic Engine | In English | → Mechanical engineering |
| NIH | National Institutes of Health (www.nih.gov) | In English | → Research institutes → Medicine → Biological sciences |
| NIIF | Normas Internacionales de Información Financiera = IFRS | International Financial Reporting Standards | In English = МСФО | Международные стандарты финансовой отчётности | In Russian = IFRS | 国际财务报告准则 | In Chinese = ΔΠΧΠ | Διεθνή Πρότυπα Χρηματοοικονομικής Πληροφόρησης | In Greek |
In Spanish | → Accounting |
| NIM | Nuclear Instrumentation Module | In English | → Nuclear technology |
| NIMH | National Institute of Mental Health | In English | → Neurology |
| NIMP | Nuclear Instruments and Methods in Physics Research | In English | → Serial publications, periodicals → Nuclei → Nuclear technology |
| NIMS | National Institute for Materials Science (www.nims.go.jp) | In English | → Research institutes → 620 |
| NIOSH | National Institute for Occupationnal Safety and Health | In English | → Labour, labour economics → Medicine |
| NIOSH | National Institute for Occupational Safety and Health | In English | → Labour, labour economics → Medicine |
| NIPS | National Institute for Physiological Sciences | In English | → Research institutes → Physiology |
| NIR | (Belgisch) Nationaal Instituut voor Radio-omroep | In Dutch | → Telecommunications |
| NIST | National Institute of Standards and Technology (www.nist.gov) | In English | → Standardization → Engineering, technology |
| NIST | National Institute for Standardization and Technology (www.nist.gov) | In English | → Standardization → Engineering, technology |
| NISTJ | National Institute of Standards and Technology Journal of Research | In English | → Serial publications, periodicals → Standardization → Engineering, technology |
| NITLE | National Institute for Technology and Liberal Education | In English | → Education → Engineering, technology |
| NITZ | Network Identity Time Zone | In English | → Telecommunications |
| NKI-AVL | Nederlands Kanker Instituut - Antoni van Leeuwenhoek Ziekenhuis | In Dutch | → Oncology |
| NLA | National Leather Association (www.nla-i.com) | In English | → Associations → Leather industry |
| NLO | Neidentifikovani leteći objekat = NIFO, OVNI, НЛО, UFO, עב"מ, NOL, OZN (look above) |
In Serbo-Croatian | → Spaceflight engineering, astronautics |
| NLO | Neidentificēts lidojošs objekts = NIFO, OVNI, НЛО, UFO, עב"מ, NOL, OZN (look above) |
In Latvian | → Spaceflight engineering, astronautics |
| NLR | Nationaal Lucht- en Ruimtevaartlaboratorium | In Dutch | → Research institutes → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| NMAB | National Materials Advisory Board | In English | → Organizations and associations → 620 |
| NMBS | Nationale Maatschappij der Belgische Spoorwegen (www.b-rail.be) = SNCB | Société Nationale des Chemins de fer Belges | In French |
In Dutch | → Rail transport engineering → Transport and postal services |
| NMC | Nursing and Midwifery Council | In English | → Organizations and associations → Medicine |
| NMCC | National Military Command Center | In English | → Military engineering |
| NMI | NASA Management Instruction | In English | → Management → Spaceflight engineering, astronautics |
| NMI | National Maritime Institute | In English | → Marine research, oceanography → 627 → 6295 |
| NMI | Naturwissenchaftlich-Medizinisches Institut | In English | → Biological sciences → Medicine |
| NMMBC | Neuropathie Motrice Multifocale à Bloc de Conduction | In French | → Neurology |
| NMOS | Negative-Type Metal Oxide Semiconductor | In English | → Electronics |
| NMPP | Nouvelles Messageries de la Presse Parisienne | In French | → Newspapers, journalism → Graphic industries, printing, publishing |
| NMR | Nuclear Magnetic Resonance = RMN | Résonance Magnétique Nucléaire | In French = RMN | Ressonància Magnètica Nuclear | In Catalan = RMN | Risonanza Magnetica Nucleare | In Italian = תמ"ג | תהודה מגנטית גרעינית | In Hebrew = ЯМР | Я́дерного магни́тного резона́нса | In Russian = НМР | Нуклеарна магнетна резонанција | In Serbian |
In English | → Medicine → Nuclear, atomic, and molecular physics → 629031 |
| NMTA | National Metal Trades Association | In English | → Associations → Trade → Metallurgy |
| NMTBA | National Machine Tool BUilders' Association | In English | → Associations → Mechanical engineering |
| NMTS | Next Manned Transportation System | In English | → Vehicle engineering |
| NN | Neural Networks | In English | → Serial publications, periodicals → Computer-based techniques → Neurology |
| NNPT | Nuclear Non-Proliferation Treaty | In English | → International relations → Nuclear technology → Military engineering |
| NNSA | National Nuclear Security Administration | In English | → Central administration → Nuclear technology |
| NOA | National Outsourcing Association | In English | → Associations → Telecommunications |
| NOES | National Operational Environmental Satellite | In English | → Environment, environmental sciences → Spaceflight engineering, astronautics |
| NOL | Niezidentyfikowany Obiekt Latający = NIFO, OVNI, НЛО, UFO, עב"מ, NLO, OZN (look above) |
In Polish | → Spaceflight engineering, astronautics |
| NOMIS | Nuclear Operations and Maintenance Information Service | In English | → Maintenance and logistics → Nuclear technology |
| NORAD | North American Air Defense Command | In English | → 358 → Military engineering → Aeronautics, aircraft |
| NORAD | North American Aerospace Defense Command | In English | → 358 → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| NOSS | National Oceanic Satellite System | In English | → Marine research, oceanography → Spaceflight engineering, astronautics |
| NPC | NASA Procurement Circular | In English | → Spaceflight engineering, astronautics |
| NPC | NASA Publication Control | In English | → Spaceflight engineering, astronautics |
| NPD | NASA Policy Directive | In English | → Management → Spaceflight engineering, astronautics |
| NPG | Nature Publishing Group | In English | → Serial publications, periodicals → Graphic industries, printing, publishing |
| NPH | Neutral Protamine Hagedorn | In English | → Cardiology |
| NPL | Normal Power Level | In English | → Electrical engineering |
| NPN | NASA Part Number | In English | → Spaceflight engineering, astronautics |
| NPO | Nederlandse Publieke Omroep (www.omroep.nl) | In Dutch | → Telecommunications |
| NPS | Nuclear Power Station | In English | → Nuclear technology |
| NPS | NASA Planning Studies | In English | → Spaceflight engineering, astronautics |
| NPS | Nonpropulsive Stage | In English | → Spaceflight engineering, astronautics |
| NPSS | NASA Packet Switching System | In English | → Spaceflight engineering, astronautics |
| NPT | Navy Pointer and Tracker | In English | → 359 → Military engineering |
| NPUJ | Northwestern Polytechnical University Journal | In English | → Serial publications, periodicals |
| NRA | Nœud de Raccordement Abonné | In French | → Telecommunications |
| NRA&A | Nouvelle Revue d'Aéronautique et d'Astronautique | In French | → Serial publications, periodicals → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| NRALT | NASA Radar Altimeter | In English | → Geodesy, cartography → Spaceflight engineering, astronautics |
| NRB | Nuclear Reactor/Brayton | In English | → Nuclear technology |
| NRC | Nuclear Regulatory Commission | In English | → Nuclear technology |
| NRDS | Nuclear Rocket Development Station | In English | → Nuclear technology → Spaceflight engineering, astronautics |
| NREL | National Renewable Energy Laboratory | In English | → Research institutes → Energy economics |
| NRF | National Research Foundation | In English | → Foundations → Mathematics and natural sciences |
| NRK | Norsk Rikskringkasting (www.nrk.no) | In Norwegian | → Telecommunications |
| NRK | Nederlandse Rode Kruis | In Dutch | → Organizations and associations → Medicine |
| NRN | National Radio Network | In English | → Telecommunications |
| NRU | Natsionalna Radiokompanya Ukraïny | In Ukrainian | → Telecommunications |
| NS | Nuclear Shuttle | In English | → Nuclear technology → Spaceflight engineering, astronautics |
| NSC | NASA Standard Computer | In English | → Hardware → Spaceflight engineering, astronautics |
| NSCCA | Nuclear Safety Cross-Check Analysis | In English | → Nuclear technology |
| NSD | NASA Standard Detonator | In English | → Spaceflight engineering, astronautics |
| NSE | Nuclear Science Engineering | In English | → Serial publications, periodicals → Nuclei → Nuclear technology |
| NSI | Nanostructured Surfaces and Interfaces | In English | → Mathematics and natural sciences |
| NSI | NASA Science Internet | In English | → Internet → Spaceflight engineering, astronautics → Astronomy |
| NSI | NASA Standard Initiator | In English | → Spaceflight engineering, astronautics |
| NSIA | National Security Industrial Association | In English | → Associations → Military engineering |
| NSIF | Near-Space Instrumentation Facility | In English | → Astronomy → Spaceflight engineering, astronautics |
| NSLC | Non-Small cell Lung Carcinoma | In English | → Chest diseases → Oncology |
| NSLC | Nova Scotia Liquor Commission | In English | → 64 |
| NSLD | NASA Shuttle Logistics Depot | In English | → Maintenance and logistics → Spaceflight engineering, astronautics |
| NSO | NASA Support Operation | In English | → Spaceflight engineering, astronautics |
| NSP | NASA Support Plan | In English | → Spaceflight engineering, astronautics |
| NSTI | NASA Simulation Traffic Interface | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| NSTL | National Space Technology Laboratories | In English | → Research institutes → Astronomy → Spaceflight engineering, astronautics |
| NSTS | National Space Transportation System | In English | → Spaceflight engineering, astronautics |
| NTA | National Television Awards | In English | → Telecommunications |
| NTA | National Trappers Association | In English | → Associations → Fishing, hunting |
| NTA | National Technology Alliance | In English | → Organizations and associations → Engineering, technology |
| NTA | National Technical Association | In English | → Associations |
| NTA | Netzwerk Technikfolgenabschätzung | In German | → Organizations and associations |
| NTA | National Telecom Agency | In English | → Telecommunications |
| NTA | National Treatment Agency for Substance Misuse | In English | → Personal health and hygiene |
| NTC | Nordic Timber Council | In English | → Organizations and associations → Forestry |
| NTCo | Nondestructive Testing Communications | In English | → Serial publications, periodicals → 620 |
| NTD | NASA Test Director | In English | → Spaceflight engineering, astronautics |
| NTE | Navigation Telemetry Encoder | In English | → Geodesy, cartography → Vehicle engineering |
| NTH | NEA Transport Hogeschool | In Dutch | → Education → Transport and postal services |
| NTIS | National Technical Information Service | In English | → Engineering, technology |
| NTN | New Technology News | In English | → Serial publications, periodicals → Engineering, technology |
| NTPC | Nam Theun 2 Power Company (www.namtheun2.com) | In English | → Electrical engineering |
| NTRAC | New Technical Regulations Applications Committee | In English | → Standardization → Engineering, technology |
| NTS | Navigation Technology Satellite | In English | → Spaceflight engineering, astronautics |
| NTSC | National Television Standards Committee | In English | → Organizations and associations → Telecommunications |
| NTSC | Nuclear Technology Safety Center | In English | → Nuclear technology |
| NTSO | NASA Test Support Office | In English | → Spaceflight engineering, astronautics |
| NTT | Nippon Telegraph and Telephone (www.ntt.co.jp) | In English | → Telecommunications |
| NTU | Nanyang Technology University | In English | → Specialized or (poly)technical colleges |
| NTU | Natsionalna Telekompaniya Ukraïny (www.ntu.com.ua) = UNCITRAL | United Nations Commission on International Trade Law | In English = CNUDCI | Commission des Nations Unies pour le Droit Commercial International | In French = ЮНСИТРАЛ | Комиссия Организации Объединенных Наций по праву международной торговли | In Russian = CNUDMI | Comisión de las Naciones Unidas para el Derecho Mercantil Internacional | In Spanish = НТУ | Національна Телекомпанія України | In Ukrainian |
In Ukrainian | → Telecommunications |
| NTUA | National Technical University of Athens | In English | → Higher education, universities → Engineering, technology |
| NU | Northeast Utilities | In English | → Energy economics |
| NUAAJ | Nanjing University Aeronautics and Astronautics Journal | In English | → Serial publications, periodicals → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| NucFS | Nuclear Fusion Special Supplement | In English | → Serial publications, periodicals → Nuclei → Nuclear technology |
| NucFu | Nuclear Fusion | In English | → Serial publications, periodicals → Nuclei → Nuclear technology |
| NucIM | Nuclear Instruments and Methods | In English | → Serial publications, periodicals → Nuclei → Nuclear technology |
| NUCT | Nuova Università del Cinema e della Televisione (www.nuct.com) | In Italian | → Higher education, universities → Cinema, movies → Telecommunications |
| NucTe | Nuclear Technology | In English | → Serial publications, periodicals → Nuclei → Nuclear technology |
| NucTF | Nuclear Technology Fusion | In English | → Serial publications, periodicals → Nuclei → Nuclear technology |
| NUDET | Nuclear Detonation | In English | → Nuclear technology → Military engineering |
| NUDTJ | National University Defense Technology Journal | In English | → Serial publications, periodicals → Military engineering |
| NuEnD | Nuclear Engineering and Design | In English | → Serial publications, periodicals → Nuclei → Nuclear technology |
| NUFEM | Nagoya University Faculty Engineering Memoirs | In English | → Serial publications, periodicals → Engineering, technology |
| NUSEM | Nagoya University School Engineering Memoirs | In English | → Serial publications, periodicals → Engineering, technology |
| NUSS | NUclear Safety Standards | In English | → Nuclear technology |
| NV | Nuclear Vehicle | In English | → Nuclear technology → Vehicle engineering |
| NV | NASA Altimeter Verification | In English | → Spaceflight engineering, astronautics |
| NVAFB | North Vandenberg Air Force Base | In English | → 358 → Aeronautics, aircraft |
| nvMCJ | Nouveau variant de la Maladie de Creutzfeldt-Jakob | In French | → Neurology |
| NVR | NASA Waiver | In English | → Spaceflight engineering, astronautics |
| NVTG | Nederlandse Vereniging voor Tropische Geneeskunde | In Dutch | → Organizations and associations → Medicine |
| NWE | Nuclear Weapons Effect | In English | → Nuclear technology → Military engineering |
| NWMP | Nuclear Weapons Monitor Plan | In English | → Nuclear technology → Military engineering |
| NWP | Netherlands Water Partnership | In English | → Organizations and associations → Hydrology → Environmental technology, water supply, waste management |
| NWS | Neckarwerke Stuttgart AG | In German | → Energy economics |
| O&O | Onderzoek en Ontwikkeling = R&D | Recherche et développement | In French = F&E | Forschung und Entwicklung | In German = R&D | Research and Development | In English = I+D | Investigación y Desarrollo | In Spanish = R&S | Ricerca e Sviluppo | In Italian = P&D | Pesquisa e Desenvolvimento | In Portuguese = FoU | Forsøk og Utvikling | In Norwegian |
In Dutch | → Research policy → Engineering, technology |
| OAA | Orbiter Access Arm | In English | → Spaceflight engineering, astronautics |
| OAA | Orbiter Alternate Airfield | In English | → Spaceflight engineering, astronautics |
| OAC | Orbital Activation and Checkout | In English | → Spaceflight engineering, astronautics |
| OAFD | Orbiter Aft Flight Deck | In English | → Spaceflight engineering, astronautics |
| OAFTO | Orbiter Atmospheric Flight Test Office | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| ÖÄGM | Österreichische Ärztegesellschaft für Manuelle Medizin | In German | → Organizations and associations → Medicine |
| OAHTS | Orbiter Avionics Hardware Tracking System | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| ÖÄK | Österreichische Ärztekammer | In German | → Medicine |
| OALC | Ogden Air Logistics Center | In English | → Maintenance and logistics → Aeronautics, aircraft |
| OAME | Orbital Attitude and Maneuvering Electronics | In English | → Electronics → Spaceflight engineering, astronautics |
| OAMP | Optical Airborne Measurements Program | In English | → Aeronautics, aircraft |
| OAMS | Orbital Attitude and Maneuvering System | In English | → Spaceflight engineering, astronautics |
| ÖAMTC | Österreichischer Automobil-, Motorrad- und Touring Club | In German | → Organizations and associations → Vehicle engineering → Transport and postal services |
| OAO | Orbital Astronomical Observatory | In English | → Observatories → Spaceflight engineering, astronautics |
| OAPEC | Organization of Arab Petroleum Exporting Countries | In English | → Organizations and associations → Trade → 665 |
| OARE | Orbital Acceleration Research Experiment | In English | → Astronomy → Spaceflight engineering, astronautics |
| OARME | Oxygen Atom Reaction Materials Experiment | In English | → Nuclear, atomic, and molecular physics → Nuclear technology |
| OARS | Orbiter Avionics Radiation Specification | In English | → Aeronautics, aircraft |
| OAS | Office Automation System | In English | → Mechanical engineering |
| OAS | Orbiter Avionics Simulator | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| OAS | Orbiter Avionics System | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| OAS | Orbiter Atmospheric Simulator | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| OAS | Orbiter Aeroflight Simulator | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| OASCB | Orbiter Avionics Software Control Board | In English | → Software → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| OASIS | Orbit Avionics Software Integration Study | In English | → Software → Aeronautics, aircraft |
| OASM | Office of Aerospace Medicine | In English | → Medicine → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| OAST | Office of Aeronautics and Space Technology | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| OATS | Orbiter Avionics Tracking System | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| OBS | Operational Biomedical System | In English | → Medicine |
| OBS | Operational Bioinstrumentation System | In English | → Medicine |
| OBVP | Österreichischer Bundesverband für Psychotherapie (www.psychotherapie.at) | In German | → Organizations and associations → Psychology → Neurology |
| OCA | Orbiter Capability Assessment | In English | → Spaceflight engineering, astronautics |
| OCA | Orbiter Capability Analysis | In English | → Spaceflight engineering, astronautics |
| OCA | Ouest Convoyeur et Automatisme | In French | → Mechanical engineering |