| OCAC | Orbiter Cabin Air Cleaner | In English | → Spaceflight engineering, astronautics |
| OCALC | OKlahoma City Air Logistics Center | In English | → Maintenance and logistics → Aeronautics, aircraft |
| OCAM | Optimal Control Applications and Methods | In English | → Serial publications, periodicals → Engineering, technology |
| OCCP | Orbit Command Computer Program | In English | → Software → Spaceflight engineering, astronautics |
| OCD | Obsessive Compulsive Disorder | In English | → Psychology → Neurology |
| OCDR | Orbiter Critical Design Review | In English | → Spaceflight engineering, astronautics |
| OcEng | Ocean Engineering | In English | → Serial publications, periodicals → Marine research, oceanography → 6295 |
| OCF | Orbiter Computational Facilities | In English | → Computer science → Spaceflight engineering, astronautics |
| OCH | Orbiter Common Hardware | In English | → Hardware → Spaceflight engineering, astronautics |
| OCP | Office Chérifien des Phosphates = م ش ف | مجموعة المكتب الشريف للفوسفاط | In Arabic |
In French | → Mining → Chemical technology |
| OcPhE | Ocean Physics and Engineering | In English | → Serial publications, periodicals → Marine research, oceanography → 6295 |
| OCQ | Ordre des Chimistes du Québec | In French | → Organizations and associations → Chemistry → Chemical technology |
| OCRTAEMS | Office Central pour la Répression du Trafic des Armes, des munitions, des produits Explosifs et des Matières Sensibles | In French | → Police → Military engineering |
| OCTW | Optical Communications Through the shuttle Window | In English | → Spaceflight engineering, astronautics |
| OCW | Opzoekingscentrum voor de Wegenbouw | In Dutch | → Transport and postal services |
| ODE | Observatoire Départemental de l'Eau | In French | → Regional administration → Hydrology → Environmental technology, water supply, waste management |
| ODF | Orbit Determination Facility | In English | → Astronomy → Spaceflight engineering, astronautics |
| ÖDG | Österreichische Diabetes-Gesellschaft | In German | → Organizations and associations → Pathology |
| ODIN | Orbital Design Integration System | In English | → Spaceflight engineering, astronautics |
| ODM | Orbiter Disconnect Mechanism | In English | → Spaceflight engineering, astronautics |
| ODRC | Orbiter Data Reduction Center | In English | → Data → Spaceflight engineering, astronautics |
| OEAS | Orbital Emergency Arresting System | In English | → Spaceflight engineering, astronautics |
| OEC | Olfactory Ensheathing Cell | In English | → Anatomy |
| OECI | Organisation of European Cancer Institutes | In English | → Organizations and associations → Oncology |
| OECI | Organization of European Cancer Institutes (www.oeci-eeig.org) | In English | → Organizations and associations → Research institutes → Oncology |
| OECO | Outboard Engine Cutoff | In English | → Vehicle engineering |
| OECS | Orbital Express Capture System | In English | → Spaceflight engineering, astronautics |
| OEGGG | Österreichische Gesellschaft für Gynäkologie und Geburtshilfe (www.oeggg.at) | In German | → Organizations and associations → Gynaecology → Obstetrics |
| OEM | Original Equipment Manufacturer | In English | → Engineering, technology |
| OEPS | Operationally Efficient Propulsion System | In English | → Vehicle engineering |
| OES | Orbiter Emergency Site | In English | → Spaceflight engineering, astronautics |
| OEST | Observatoire Économique et Statistique des Transports | In French | → Statistics → Economics → Transport and postal services |
| OET | Orbiter Engineering and Test | In English | → Spaceflight engineering, astronautics |
| OEW | Oberschwäbische Elektrizitätswerke | In German | → Electrical engineering |
| OEX | Orbiter Experiment | In English | → Spaceflight engineering, astronautics |
| OF | Orbital Flight | In English | → Spaceflight engineering, astronautics |
| OFBSL | Observatoire de la Foresterie du Bas-Saint-Laurent | In French | → Environment, environmental sciences → Agricultural sciences |
| OFDM | Orthogonal Frequency Division Multiplexing | In English | → Networks, communication → Telecommunications |
| OFDS | Orbiter Flight Dynamic Simulator | In English | → Computer simulation → Spaceflight engineering, astronautics |
| OFEFP | Office Fédéral de l'Environnement, des Forêts et du Paysage | In French | → Public administration, government → Nature → Forestry |
| ÖFG | Österreichische Forschungsgemeinschaft | In German | → Research policy → Mathematics and natural sciences |
| OFI | Operational Flight Instrumentation | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| OFK | Optical Flight Kit | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| OFP | Operational Flight Program | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| OFP | Operational Flight Profile | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| OFP | Orbiter Flight Program | In English | → Spaceflight engineering, astronautics |
| OFP | Omnium Français des Pétroles | In French | → 665 |
| OFS | Orbital/Orbital Flight System | In English | → Spaceflight engineering, astronautics |
| OFS | Orbiter Functional Simulator | In English | → Spaceflight engineering, astronautics |
| OFS | Orbiter Flight Simulator | In English | → Spaceflight engineering, astronautics |
| OFT | Operational Flight Test | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| OFT | Orbital Flight Test | In English | → Spaceflight engineering, astronautics |
| OFT | Orbital Flight Training | In English | → Spaceflight engineering, astronautics |
| OFTDS | Orbital Flight Test Data System | In English | → Data → Spaceflight engineering, astronautics |
| ÖGA | Österreichische Gesellschaft für Akupunktur | In German | → Medicine |
| ÖGAI | Österreichische Gesellschaft für Allergologie und Immunologie | In German | → Organizations and associations → Immunology and allergy |
| ÖGAM | Österreichische Gesellschaft für Allgemeinmedizin | In German | → Organizations and associations → Medicine |
| ÖGARI | Österreichische Gesellschaft für Anaesthesiologie, Reanimation und Intensivmedizin | In German | → Organizations and associations → Traumatology → Anesthesiology |
| ÖGDV | Österreichische Gesellschaft für Dermatologie und Venerologie | In German | → Organizations and associations → Dermatology |
| ÖGGG | Österreichische Gesellschaft für Geriatrie und Gerontologie | In German | → Organizations and associations → Gerontology |
| ÖGGH | Österreichische Gesellschaft für Gastroenterologie und Hepatologie | In German | → Organizations and associations → Pathology |
| ÖGHO | Österreichische Gesellschaft für Hämatologie und Onkologie | In German | → Organizations and associations → Oncology |
| ÖGI | Österreichisches Gießerei-Institut | In German | → Research institutes → Metallurgy |
| ÖGI | Österreichisches Getränke-Institut | In German | → Research institutes → Beverage industry |
| ÖGIM | Österreichische Gesellschaft für Innere Medizin | In German | → Organizations and associations → Medicine |
| ÖGK | Österreichisches Grünes Kreuz (www.gruenes-kreuz.org) | In German | → Organizations and associations → Medicine |
| OGK | Optovaya Giéniérirouyouchtchaya Kompaniya = ОГК | Оптовая генерирующая компания | In Russian |
In Russian | → Energy economics → Electrical engineering |
| OGKA | Österreichische Gesellschaft für kontrollierte Akupunktur | In German | → Organizations and associations → Medicine |
| ÖGKC | Österreichische Gesellschaft für klinische Chemie | In German | → Organizations and associations → Biochemistry, biophysics → Pharmacology, toxicology |
| ÖGKJ | Österreichische Gesellschaft für Kinder- und Jugendheilkunde (www.docs4you.at) | In German | → Organizations and associations → Pediatry |
| ÖGLUT | Österreichische Gesellschaft für Lungenerkrankungen und Tuberkulose | In German | → Organizations and associations → Chest diseases → Infectious diseases |
| OGM | Organisme Génétiquement Modifié | In French | → Biological sciences → Biotechnology |
| OGMT | Orbiter Greenwich Mean Time | In English | → Spaceflight engineering, astronautics |
| ÖGN | Österreichische Gesellschaft für Neurologie | In German | → Organizations and associations → Neurology |
| ÖGN | Österreichische Gesellschaft für Nuklearmedizin | In German | → Organizations and associations → Medicine |
| ÖGP | Österreichische Gesellschaft für Pneumologie | In German | → Organizations and associations → Chest diseases |
| ÖGPB | Österreichische Gesellschaft für Neuropsychopharmakologie und Biologische Psychiatrie | In German | → Organizations and associations → Pharmacology, toxicology → Neurology → Psychiatry |
| ÖGPH | Österreichische Gesellschaft für Public Health | In German | → Organizations and associations → Medicine |
| ÖGPMR | Österreichische Gesellschaft für Physikalische Medizin und Rehabilitation | In German | → Organizations and associations → Medicine |
| ÖGRME | Österreichische Gesellschaft für Reproduktionsmedizin und Endokrinologie | In German | → Organizations and associations → Gynaecology |
| ÖGS | Österreichische Gesellschaft für Senologie | In German | → Organizations and associations → Medicine |
| ÖGSMSF | Österreichische Gesellschaft für Schlafmedizin und Schlafforschung | In German | → Organizations and associations → Medicine |
| ÖGT | Österreichische Gesellschaft für Tuina | In German | → Medicine |
| ÖGUM | Österreichische Gesellschaft für Ultraschall in der Medizin | In German | → Organizations and associations → Medicine |
| OHA | Orbital Height Adjustment Maneuver | In English | → Spaceflight engineering, astronautics |
| OHF | Occupational Health Facility | In English | → Labour, labour economics → Medicine |
| OHGVT | Orbital Horizontal Ground Vibration Test | In English | → Spaceflight engineering, astronautics |
| OHSU | Oregon Health and Science University (www.ohsu.edu) | In English | → Higher education, universities → Mathematics and natural sciences → Medicine |
| OI | Orbiter Insertion | In English | → Spaceflight engineering, astronautics |
| OI | Orbiter Instrumentation | In English | → Spaceflight engineering, astronautics |
| OIA | Orbiter Interface Adapter | In English | → Human-computer interaction → Spaceflight engineering, astronautics |
| OIAC | Organisation pour l'Interdiction des Armes Chimiques (www.opcw.org) = OPWC | Organisation for the Prohibition of Chemical Weapons | In English |
In French | → Organizations and associations → International relations → Military engineering |
| ÖIAT | Österreichisches Institut für angewandte Telekommunikation | In German | → Research institutes → Telecommunications |
| OIB | Österreichisches Institut für Bautechnik | In German | → Building |
| OIBT | Organisation Internationale des Bois Tropicaux (www.itto.or.jp) = ITTO | International Tropical Timber Organization | In English = OIMT | Organización Internacional de las Maderas Tropicales | In Spanish |
In French | → Organizations and associations → Nature and society → Timber and woodworking industry |
| OIC | Orbital Integrated Checkout | In English | → Spaceflight engineering, astronautics |
| OIE | Orbiter Integration Engineering | In English | → Spaceflight engineering, astronautics |
| OIE | Oficina per a la Innovació Empresarial | In Catalan | → Engineering, technology |
| OIE | Office International des Épizooties | In French | → Veterinary medicine |
| OIEA | Organismo Internacional de Energía Atómica (www.iaea.org) = IAAE | Internacia Agentejo pri Atom-Energio | In Esperanto = IAEA | International Atomic Energy Agency | In English = AIEA | Agence Internationale de l'Énergie Atomique | In French = AIEA | Agenţia Internaţională pentru Energie Atomică | In Romanian = МААЕ | Международна агенция за атомна енергия | In Bulgarian = AIEA | Agència Internacional de l'Energia Atòmica | In Catalan = MAAE | Mezinárodní agentura pro atomovou energii | In Czech = IAEA | Det Internationale Atomenergiagentur | In Danish = IAEO | Internationale Atomenergieorganisation | In German = סבא"א | הסוכנות הבינלאומית לאנרגיה אטומית | In Hebrew = IAEA | International Atomenergie Agence | In Letzeburgesh = AIEA | Agenzia Internazionale per l'Energia Atomica | In Italian = IAEA | अंतर्राष्ट्रीय परमाणु ऊर्जा अधिकरण | In Hindi = MAAE | Меѓународна агенција за атомска енергија | In Macedonian = МАГАТЭ | Международное агентство по атомной энергии | In Russian = AIEA | Agência Internacional de Energia Atómica | In Portuguese = MAEA | Międzynarodowa Agencja Energii Atomowej | In Polish = МАГАТЕ | Міжнародне агентство з атомної енергії | In Ukrainian = UAEA | Uluslararası Atom Enerji Ajansı | In Turkish = IAEA | สำนักงานพลังงานปรมาณูระหว่างประเทศ | In Thai = EANA | Energia Atomikoaren Nazioarteko Agentzia | In Basque |
In Spanish | → International relations → Energy economics → Nuclear technology |
| OIEau | Office International de l'Eau | In French | → Organizations and associations → Hydrology → Environmental technology, water supply, waste management |
| OIF | Osteogenesis Imperfecta Foundation | In English | → Foundations → Pathology |
| OIMT | Organización Internacional de las Maderas Tropicales (www.itto.or.jp) = OIBT, ITTO (look above) |
In Spanish | → Organizations and associations → Nature and society → Timber and woodworking industry |
| OIP | Omnium International des Pétroles | In French | → 665 |
| OIS | Orbit Insertion Subsystem | In English | → Spaceflight engineering, astronautics |
| OIS | Orbit Inserting System | In English | → Spaceflight engineering, astronautics |
| OIS | Orbit Injection Subsystem | In English | → Spaceflight engineering, astronautics |
| OIS | Operational Intercommunication System | In English | → Telecommunications |
| OIS | Orbiter Instrumentation Systems | In English | → Spaceflight engineering, astronautics |
| OISTP | Oxygen-Iodine SUpersonic Technology Program | In English | → Aeronautics, aircraft |
| OIT | Orbiter Interface Test | In English | → Spaceflight engineering, astronautics |
| OIT | Orbiter Integration Test | In English | → Spaceflight engineering, astronautics |
| OIT | Orbiter Integrated Test | In English | → Spaceflight engineering, astronautics |
| OIV | Organisation Internationale de la Vigne et du Vin | In French | → Organizations and associations → Agricultural sciences → Beverage industry |
| OIVS | Orbiter Interface Verification Set | In English | → Spaceflight engineering, astronautics |
| OJD | Office de Justification de la Diffusion des Supports de Publicité | In French | → 6591 |
| ÖKG | Österreichische Kardiologische Gesellschaft | In German | → Organizations and associations → Cardiology |
| OKTVF | Országos Környezetvédelmi, Természetvédelmi és Vízügyi Főigazgatóság | In Hungarian | → 626 → 627 |
| OLERD | Orbiter Landing Emergency Rescue Data | In English | → Spaceflight engineering, astronautics |
| OLF | Orbiter Lifting Frame | In English | → Spaceflight engineering, astronautics |
| OLIF | ORbiter Landing Instrumentation Facility | In English | → Spaceflight engineering, astronautics |
| OLOW | Orbiter Lift-Off Weight | In English | → Spaceflight engineering, astronautics |
| OLSP | Orbiter Logistics Support Plan | In English | → Spaceflight engineering, astronautics |
| OLT | Optical Line Terminal | In English | → Telecommunications |
| OMA | Orbiter Maintenance Area | In English | → Maintenance and logistics → Spaceflight engineering, astronautics |
| OMBUU | Orbiter Midbody Umbilical Unit | In English | → Spaceflight engineering, astronautics |
| ÖMCCV | Österreichische Morbus Crohn-Colitis ulcerosa Vereinigung | In German | → Pathology |
| OMCF | Orbiter Maintenance and Checkout Facility | In English | → Maintenance and logistics → Spaceflight engineering, astronautics |
| OMCS | Operations and Maintenance Communications System | In English | → Maintenance and logistics → Telecommunications |
| OMDP | Orbiter Maintenance Down Period | In English | → Maintenance and logistics → Spaceflight engineering, astronautics |
| OME | Orbiter Main Engine | In English | → Spaceflight engineering, astronautics |
| OME | Orbital Maneuvering Engine | In English | → Spaceflight engineering, astronautics |
| OMEC | Organic Materials for Electronics Consortium | In English | → Chemistry → Electronics |
| OMET | Orbiter Mission Elapsed Time | In English | → Spaceflight engineering, astronautics |
| OMEWG | Orbiter Maintenance Engineering Working Group | In English | → Maintenance and logistics → Spaceflight engineering, astronautics |
| OMI | Organisation Maritime Internationale = IMO | International Maritime Organization | In English = IMO | Internacia Mar-Organizo | In Esperanto |
In French | → International relations → Marine research, oceanography → 6295 → Agricultural sciences |
| OMK | Orbiter Mission Kit | In English | → Spaceflight engineering, astronautics |
| OML | Orbiter Mold Line | In English | → Spaceflight engineering, astronautics |
| OML | Outer Mold Line | In English | → Metallurgy |
| OML | Oddział Metali Lekkich | In Polish | → Research institutes → Metallurgy |
| OMMH | Orbiter Maintenance Man-Hour | In English | → Maintenance and logistics → Spaceflight engineering, astronautics |
| OMR | Orbiter Management Review | In English | → Spaceflight engineering, astronautics |
| OMRF | Orbiter Maintenance and Refurbishment Facility | In English | → Maintenance and logistics → Spaceflight engineering, astronautics |
| OMRF | Orbiter Modification and Refurbishment Facility | In English | → Maintenance and logistics → Spaceflight engineering, astronautics |
| OMS | Organisacion mondiâla de la sandât = MOS | Monda Organiz(aĵ)o pri Sano | In Esperanto = WHO | World Health Organization | In English = OMS | Organisation Mondiale de la Santé | In Esperanto = OMS | Organizzazione Mondiale della Sanità | In Italian = WGO | Wêreldgesondheidsorganisasie | In Afrikaans = OMS | Organización Mundial de la Salú | In Asturian = СЗО | Световната здравна огранизация | In Bulgarian = SZO | Světová zdravotnická organizace | In Czech = OMS | Organització Mundial de la Salut | In Catalan = OMS | Organización Mundial de la Salud | In Spanish = MTO | Maailma Terviseorganisatsioon | In Estonian = MOE | Munduko Osasun Erakundea | In Basque = OMS | Organización Mundial da Saúde | In Galician = SZO | Svjetska zdravstvena organizacija | In Croatian = RTD | Rêxistina Tendurustiyê ya Dinyayê | In Kurdish = UMS | Urganizazziun mundiala da la Santaa | In Lombard = PSO | Pasaulio sveikatos organizacija | In Lithuanian = PVO | Pasaules veselības organizācija | In Latvian |
[FRP] | → United Nations → Medicine |
| OMS | Organizzazione Mondiale della Sanità = MOS, WHO, WGO, СЗО, SZO, MTO, MOE, RTD, UMS, PSO, PVO (look above) |
In Italian | → United Nations → Medicine |
| OMS | Organización Mundial de la Salú = MOS, WHO, WGO, СЗО, SZO, MTO, MOE, RTD, UMS, PSO, PVO (look above) |
In Asturian | → United Nations → Medicine |
| OMS | Organización Mundial da Saúde = MOS, WHO, WGO, СЗО, SZO, MTO, MOE, RTD, UMS, PSO, PVO (look above) |
In Galician | → United Nations → Medicine |
| OMS | Organización Mundial de la Salud = MOS, WHO, WGO, СЗО, SZO, MTO, MOE, RTD, UMS, PSO, PVO (look above) |
In Spanish | → United Nations → Medicine |
| OMS | Organització Mundial de la Salut = MOS, WHO, WGO, СЗО, SZO, MTO, MOE, RTD, UMS, PSO, PVO (look above) |
In Catalan | → United Nations → Medicine |
| OMS | Organisation Mondiale de la Santé = MOS, WHO, WGO, СЗО, SZO, MTO, MOE, RTD, UMS, PSO, PVO (look above) |
In Esperanto | → United Nations → Medicine |
| OMS | Orbital Maneuvering System | In English | → Spaceflight engineering, astronautics |
| OMSP | Organización Mundial de la Salud Pública | In Spanish | → Organizations and associations → International relations → Public health and hygiene |
| OMT | Osteopathic Manipulative Treatment | In English | → Medicine |
| OMT | Ortopedisen Manuaalisen Terapian | In Finnish | → Medicine |
| OMT | Ortopedisk manuell terapi | In Swedish | → Surgery, orthopaedics, ophthalmology |
| OMT | Oberflächen- und Materialtechnologie GmbH | In German | → 620 |
| OMV | Orbital Maneuvering Vehicle | In English | → Spaceflight engineering, astronautics |
| ONA | Organizo por Nutrado kaj Agrikulturo = FAO | Food and Agriculture Organization | In English |
In Esperanto | → International relations → Agricultural sciences → Food technology |
| ONBAH | Office National des Barrages et des Aménagements Hydro-agricoles | In French | → Central administration → 627 → Agricultural sciences |
| ONBT | Orbiter Neutral Buoyancy Trainer | In English | → Spaceflight engineering, astronautics |
| ONC | Office National de la Chasse | In French | → Central administration → Fishing, hunting |
| ONCF | Office National des Chemins de Fer | In French | → Transport and postal services |
| ONE | Office National d’Électricité | In French | → Central administration → Electrical engineering |
| ONEP | Office National de l'Eau Potable | In French | → Organizations and associations → Environmental technology, water supply, waste management |
| ONERA | Office National d'Études et de Recherches Aéronautiques | In French | → Aeronautics, aircraft |
| ONERA | Office National d'Études et de Recherches Aérospatiales | In French | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| ONF | Office National des Forêts | In French | → Central administration → Forestry |
| ONISR | Observatoire National Interministériel de la Sécurité Routière | In French | → Central administration → Transport and postal services |
| ONR | Office of Naval Research | In English | → Military engineering |
| ONREK | Office National de Recherche et d'Évaluation en Kinésithérapie | In French | → Medicine |
| OOD | Orbiter On Dock | In English | → Spaceflight engineering, astronautics |
| OOH | Orbital Operations Handbook | In English | → Spaceflight engineering, astronautics |
| OOR | On-Orbit Review | In English | → Spaceflight engineering, astronautics |
| OOS | On-Orbit Station | In English | → Spaceflight engineering, astronautics |
| OOS | Orbit-to-Orbit Shuttle | In English | → Spaceflight engineering, astronautics |
| OOS | Orbit-to-Orbit Stage | In English | → Spaceflight engineering, astronautics |
| OOSD | Orbital Operations Support Document | In English | → Spaceflight engineering, astronautics |
| OOSD | On-Orbit Support Document | In English | → Spaceflight engineering, astronautics |
| OOSDP | On-Orbit Station Distribution Panel | In English | → Spaceflight engineering, astronautics |
| OOSS | On-Orbit Support System | In English | → Spaceflight engineering, astronautics |
| OPA | Online Publishers Association | In English | → Organizations and associations → Graphic industries, printing, publishing |
| OPAC | Office Public d'Aménagement et de Construction | In French | → Accommodation → Building |
| OPAS | Organização Pan-Americana da Saúde (www.paho.org) = OPS | Organización Panamericana de la Salud | In Spanish = PAHO | Pan American Health Organization | In English |
In Portuguese | → Organizations and associations → International relations → Medicine |
| OPB | Oxidizer Preburner | In English | → Vehicle engineering |
| OPBS | Orbiter Payload Bay Simulator | In English | → Spaceflight engineering, astronautics |
| OPDQ | Ordre Professionnel des Diététistes du Québec | In French | → Organizations and associations → Personal health and hygiene |
| OPEC | Organization of the Petroleum Exporting Countries = OPEP | Organisation des Pays Exportateurs de Pétrole | In French = OPEC | Organization of Petroleum Exporting Countries | In English = OPEL | Organizaĵo de Petrol-Eksportaj Landoj | In Esperanto = OPEP | Organização dos Países Exportadores de Petróleo | In Portuguese = OPEP | Organización de Países Esportadores de Petroleu | In Asturian = OPEP | Organización de Países Exportadores de Petróleo | In Spanish = OPEP | Organització de Països Exportadors de Petroli | In Catalan = ОПЕК | Организација на земји извознички на нафта и нафтени деривати | In Macedonian |
In English | → Organizations and associations → Mining → 665 |
| OPEC | Organization of Petroleum Exporting Countries = OPEP, OPEL, ОПЕК (look above) |
In English | → Organizations and associations → Mining → 665 |
| OPECST | Office Parlementaire d'Évaluation des Choix Scientifiques et Technologiques | In French | → Research policy → Politics → Engineering, technology |
| OPEL | Organizaĵo de Petrol-Eksportaj Landoj = OPEC, OPEP, ОПЕК (look above) |
In Esperanto | → Organizations and associations → Mining → 665 |
| OPEN | Organisation de Producteurs d'Énergie Nucléaire | In French | → Organizations and associations → Nuclear technology |
| OPEP | Organização dos Países Exportadores de Petróleo = OPEC, OPEL, ОПЕК (look above) |
In Portuguese | → Organizations and associations → Mining → 665 |
| OPEP | Organisation des Pays Exportateurs de Pétrole = OPEC, OPEL, ОПЕК (look above) |
In French | → Chemical technology → Mining → 665 |
| OPEP | Organización de Países Esportadores de Petroleu = OPEC, OPEL, ОПЕК (look above) |
In Asturian | → Organizations and associations → Mining → 665 |
| OPEP | Organització de Països Exportadors de Petroli = OPEC, OPEL, ОПЕК (look above) |
In Catalan | → Organizations and associations → Mining → 665 |
| OPEP | Organización de Países Exportadores de Petróleo = OPEC, OPEL, ОПЕК (look above) |
In Spanish | → Organizations and associations → Mining → 665 |
| OPF | Orbiter Processing Facility | In English | → Spaceflight engineering, astronautics |
| OPI | Office du Périmètre d'Irrigation | In French | → Public administration, government → Agricultural sciences |
| OPI | Orbiter Payload Interrogator | In English | → Spaceflight engineering, astronautics |