

| Acronym | Sense | Language | Topics | 
|---|---|---|---|
| Co | コバルト = Co | Cobalt | In French = Co | Kobalt | In Afrikaans = Co | كوبالت | In Arabic = Co | Kobalt | In Azerbaijani = Co | Кобальт | In Belarusian = Co | Кобалт | In Bulgarian = Co | কোবাল্ট | In Bengali = Co | Kobalt | In Bosnian = Co | Cobalt | In Catalan = Co | Cobaltu | In Corsican = Co | Kobalt | In Czech = Co | Кобальт | In Chuvash = Co | Kobolt | In Danish = Co | Cobalt | In German = Co | Κοβάλτιο | In Greek = Co | Cobalt | In English = Co | Kobalto | In Esperanto = Co | Cobalto | In Spanish = Co | Koobalt | In Estonian = Co | Kobalto | In Basque = Co | کبالت | In Persian = Co | Koboltti | In Finnish = Co | Cobalt | In Friulian = Co | Cóbalt | In Irish = Co | Cobalto | In Galician = Co | Cobalt | In Manx = Co | קובלט | In Hebrew = Co | कोबाल्ट | In Hindi = Co | Kobalt | In Croatian = Co | Kobalt | In Hungarian = Co | Կոբալտ | In Armenian = Co | Kobal | In Indonesian = Co | Kobalto | In Ido = Co | Kóbolt | In Icelandic = Co | Cobalto | In Italian = Co | ridjinme | In Lojban = Co | ಕೊಬಾಲ್ಟ್ | In Kannada = Co | 코발트 | In Korean = Co | Kobalt | In Kurdish = Co | Cobaltum | In Latin = Co | Kobalt | In Letzeburgesh = Co | Kobaltas | In Lithuanian = Co | Kobalts | In Latvian = Co | Кобалт | In Macedonian = Co | കൊബാള്ട്ട് | In Malayalam = Co | कोबाल्ट | In Marathi = Co | Kobalt | In Low German = Co | Kobalt | In Dutch = Co | Kobolt | In Nynorsk = Co | Kobolt | In Norwegian = Co | Cobalt | In Occitan = Co | Kobalt | In Polish = Co | Cobalto | In Portuguese = Co | Kubaltu | In Quechua = Co | Cobalt | In Romanian = Co | Кобальт | In Russian = Co | Kobalt | In Serbo-Croatian = Co | Kobalt | In Slovak = Co | Kobalt | In Slovenian = Co | Кобалт | In Serbian = Co | Cobalt | In Saterland Frisian = Co | Kobolt | In Swedish = Co | Kobalti | In Swahili = Co | Кобалт | In Tajik = Co | โคบอลต์ | In Thai = Co | Kobalt | In Turkish = Co | Кобальт | In Ukrainian = Co | Kobalt | In Uzbek = Co | Coban | In Vietnamese = Co | 钴 | In Chinese | In Japanese | → Chemistry | 
| Co | ridjinme = (look above) | In Lojban | → Chemistry | 
| Co | ಕೊಬಾಲ್ಟ್ = (look above) | In Kannada | → Chemistry | 
| Co | 코발트 = (look above) | In Korean | → Chemistry | 
| Co | Kobalt = (look above) | In Kurdish | → Chemistry | 
| Co | Cobaltum = (look above) | In Latin | → Chemistry | 
| Co | Kobalt = (look above) | In Letzeburgesh | → Chemistry | 
| Co | Kobaltas = (look above) | In Lithuanian | → Chemistry | 
| Co | Kobalts = (look above) | In Latvian | → Chemistry | 
| Co | Кобалт = (look above) | In Macedonian | → Chemistry | 
| Co | കൊബാള്ട്ട് = (look above) | In Malayalam | → Chemistry | 
| Co | कोबाल्ट = (look above) | In Marathi | → Chemistry | 
| Co | Kobalt = (look above) | In Low German | → Chemistry | 
| Co | Kobalt = (look above) | In Dutch | → Chemistry | 
| Co | Kobolt = (look above) | In Nynorsk | → Chemistry | 
| Co | Kobolt = (look above) | In Norwegian | → Chemistry | 
| Co | Cobalt = (look above) | In Occitan | → Chemistry | 
| Co | Kobalt = (look above) | In Polish | → Chemistry | 
| Co | Cobalto = (look above) | In Portuguese | → Chemistry | 
| Co | Kubaltu = (look above) | In Quechua | → Chemistry | 
| Co | Cobalt = (look above) | In Romanian | → Chemistry | 
| Co | Кобальт = (look above) | In Russian | → Chemistry | 
| Co | Kobalt = (look above) | In Serbo-Croatian | → Chemistry | 
| Co | Kobalt = (look above) | In Slovak | → Chemistry | 
| Co | Kobalt = (look above) | In Slovenian | → Chemistry | 
| Co | Кобалт = (look above) | In Serbian | → Chemistry | 
| Co | Cobalt = (look above) | In Saterland Frisian | → Chemistry | 
| Co | Kobolt = (look above) | In Swedish | → Chemistry | 
| Co | Kobalti = (look above) | In Swahili | → Chemistry | 
| Co | Кобалт = (look above) | In Tajik | → Chemistry | 
| Co | โคบอลต์ = (look above) | In Thai | → Chemistry | 
| Co | Kobalt = (look above) | In Turkish | → Chemistry | 
| Co | Кобальт = (look above) | In Ukrainian | → Chemistry | 
| Co | Kobalt = (look above) | In Uzbek | → Chemistry | 
| Co | Coban = (look above) | In Vietnamese | → Chemistry | 
| Co | 钴 = (look above) | In Chinese | → Chemistry | 
| CO | Commissioned Officer | In English | → Military affairs | 
| CO | Monoxyde de carbone = CO | أول أكسيد الكربون | In Arabic = CO | Monòxid de carboni | In Catalan = CO | Oxid uhelnatý | In Czech = CO | Kulilte | In Danish = CO | Kohlenstoffmonoxid | In German = CO | Carbon monoxide | In English = CO | Karbona monooksido | In Esperanto = CO | Monóxido de carbono | In Spanish = CO | Vingugaas | In Estonian = CO | Karbono monoxido | In Basque = CO | منو اکسید کربن | In Persian = CO | Hiilimonoksidi | In Finnish = CO | Monóxido de carbono | In Galician = CO | Carboan monocseed | In Manx = CO | פחמן חד-חמצני | In Hebrew = CO | Ugljikov monoksid | In Croatian = CO | Wuhlikowy monoksid | In Upper Sorbian = CO | Szén-monoxid | In Hungarian = CO | Karbon monoksida | In Indonesian = CO | Kolmónoxíð | In Icelandic = CO | Monossido di carbonio | In Italian = CO | 一酸化炭素 | In Japanese = CO | 일산화 탄소 | In Korean = CO | Monoxidum Carbonis | In Latin = CO | Anglies monoksidas | In Lithuanian = CO | Oglekļa monoksīds | In Latvian = CO | Јаглерод моноксид | In Macedonian = CO | कार्बन मोनॉक्साईड | In Marathi = CO | Koolstofmonoxide | In Dutch = CO | Karbonmonoksid | In Nynorsk = CO | Karbonmonoksid | In Norwegian = CO | Tlenek węgla | In Polish = CO | Monóxido de carbono | In Portuguese = CO | Monoxid de carbon | In Romanian = CO | Монооксид углерода | In Russian = CO | Oxid uhoľnatý | In Slovak = CO | Ogljikov oksid | In Slovenian = CO | Karbon monoksida | In Sundanese = CO | Kolmonoxid | In Swedish = CO | Karbonmonoksit | In Turkish = CO | Монооксид вуглецю | In Ukrainian = CO | Mônôxít cacbon | In Vietnamese = CO | 一氧化碳 | In Chinese | In French | → Chemistry | 
| CO | أول أكسيد الكربون = (look above) | In Arabic | → Chemistry | 
| CO | Monòxid de carboni = (look above) | In Catalan | → Chemistry | 
| CO | Oxid uhelnatý = (look above) | In Czech | → Chemistry | 
| CO | Kulilte = (look above) | In Danish | → Chemistry | 
| CO | Kohlenstoffmonoxid = (look above) | In German | → Chemistry | 
| CO | Carbon monoxide = (look above) | In English | → Chemistry | 
| CO | Karbona monooksido = (look above) | In Esperanto | → Chemistry | 
| CO | Monóxido de carbono = (look above) | In Spanish | → Chemistry | 
| CO | Vingugaas = (look above) | In Estonian | → Chemistry | 
| CO | Karbono monoxido = (look above) | In Basque | → Chemistry | 
| CO | منو اکسید کربن = (look above) | In Persian | → Chemistry | 
| CO | Hiilimonoksidi = (look above) | In Finnish | → Chemistry | 
| CO | Monóxido de carbono = (look above) | In Galician | → Chemistry | 
| CO | Carboan monocseed = (look above) | In Manx | → Chemistry | 
| CO | פחמן חד-חמצני = (look above) | In Hebrew | → Chemistry | 
| CO | Ugljikov monoksid = (look above) | In Croatian | → Chemistry | 
| CO | Wuhlikowy monoksid = (look above) | In Upper Sorbian | → Chemistry | 
| CO | Szén-monoxid = (look above) | In Hungarian | → Chemistry | 
| CO | Karbon monoksida = (look above) | In Indonesian | → Chemistry | 
| CO | Kolmónoxíð = (look above) | In Icelandic | → Chemistry | 
| CO | Monossido di carbonio = (look above) | In Italian | → Chemistry | 
| CO | 一酸化炭素 = (look above) | In Japanese | → Chemistry | 
| CO | 일산화 탄소 = (look above) | In Korean | → Chemistry | 
| CO | Monoxidum Carbonis = (look above) | In Latin | → Chemistry | 
| CO | Anglies monoksidas = (look above) | In Lithuanian | → Chemistry | 
| CO | Oglekļa monoksīds = (look above) | In Latvian | → Chemistry | 
| CO | Јаглерод моноксид = (look above) | In Macedonian | → Chemistry | 
| CO | कार्बन मोनॉक्साईड = (look above) | In Marathi | → Chemistry | 
| CO | Koolstofmonoxide = (look above) | In Dutch | → Chemistry | 
| CO | Karbonmonoksid = (look above) | In Nynorsk | → Chemistry | 
| CO | Karbonmonoksid = (look above) | In Norwegian | → Chemistry | 
| CO | Tlenek węgla = (look above) | In Polish | → Chemistry | 
| CO | Monóxido de carbono = (look above) | In Portuguese | → Chemistry | 
| CO | Monoxid de carbon = (look above) | In Romanian | → Chemistry | 
| CO | Монооксид углерода = (look above) | In Russian | → Chemistry | 
| CO | Oxid uhoľnatý = (look above) | In Slovak | → Chemistry | 
| CO | Ogljikov oksid = (look above) | In Slovenian | → Chemistry | 
| CO | Karbon monoksida = (look above) | In Sundanese | → Chemistry | 
| CO | Kolmonoxid = (look above) | In Swedish | → Chemistry | 
| CO | Karbonmonoksit = (look above) | In Turkish | → Chemistry | 
| CO | Монооксид вуглецю = (look above) | In Ukrainian | → Chemistry | 
| CO | Mônôxít cacbon = (look above) | In Vietnamese | → Chemistry | 
| CO | 一氧化碳 = (look above) | In Chinese | → Chemistry | 
| CO | Cardiac Output | In English | → Cardiology → Blood and circulatory system | 
| COA | Center Operations Area | In English | |
| COA | Computational Optimization and Applications | In English | → Serial publications, periodicals | 
| CoA | Chart of Accounts | In English | → Accounting | 
| COA | Comptroller Of The Army | In English | → Military affairs | 
| COACHE | Collaborative on Academic Careers in Higher Education | In English | → Specialized or polytechnical colleges → Higher education, universities | 
| COAD | Centre Opérationnel d'Aide à la Décision | In French | |
| COAD | Chronisch obstruktive Atemwegserkrankung = BPCO | Broncho-Pneumopathie Chronique Obstructive | In French = COPD | Chronic Obstructive Pulmonary Disease | In English = MPOC | Maladie Pulmonaire Obstructive Chronique | In French = COLD | Chronic Obstructive Airway Disease | In English = EPOC | Enfermedad Pulmonar Obstructiva Crónica | In Spanish = BPCO | Broncopneumopatia Cronica Ostruttiva | In Italian = DPOC | Doença Pulmonar Obstrutiva Crónica | In Portuguese = KOAH | Kronik Obstrüktif Akciğer Hastalığı | In Turkish | In German | → Chest diseases | 
| COADS | Comprehensive Ocean-Atmosphere Data Set (http://icoads.noaa.gov) | In English | → Marine research, oceanography → Meteorology, climatology | 
| COAL | Coal Overseas Association Limited | In English | → Associations | 
| CoAlg | Communications in Algebra | In English | → Serial publications, periodicals → Algebra | 
| COAMPS | Coupled Ocean/Atmospheric Mesoscale Prediction System | In English | → Computer simulation → Marine research, oceanography → Meteorology, climatology | 
| COAR | City of Orange Amateur Radio | In English | → Telecommunications | 
| COARE | Coupled Ocean–Atmospheric Response Experiment (www.ncdc.noaa.gov/oa/coare/) | In English | → Marine research, oceanography → Meteorology, climatology | 
| CoArm | Contributions from the Armagh Observatory | In English | → Serial publications, periodicals → Astronomy | 
| COAS | Crewman Optical Alignment Sight | In English | |
| CoAsi | Contributions dell'Osservatorio Astrofisica dell'Universita di Padova in Asiago | In Italian | → Serial publications, periodicals → Astronomy | 
| CoASP | Comments on Astrophysics and Space Physics | In English | → Serial publications, periodicals → Astronomy | 
| COAST | Competence Network for Advanced Speech Technologies | In English | → Human-computer interaction → Computer-based techniques → Language, linguistics, literature | 
| CoAst | Communications in Asteroseismology | In English | → Serial publications, periodicals → Astronomy → Seismology, earthquakes | 
| CoAth | Contributions from the Research and Computing Center Academy of Sciences of Athens | In English | → Serial publications, periodicals → Astronomy → Greece | 
| COB | Communications Office Building | In English | → Telecommunications | 
| COB | Commission des Opérations de Bourse (www.cob.fr) | In French | → Organizations and associations → Financial markets → France | 
| COB | Chip On Board | In English | → Electronics | 
| COB | Cercle Océanaute de Bordeaux | In French | → Organizations and associations → Sport, physical exercises | 
| COB | Children Of Bodom | In English | → Music | 
| COB | Club Olympique de Billancourt | In French | → Organizations and associations → Sport, physical exercises | 
| COB | Church of the Brethren | In English | → Protestant churches | 
| COB | Club Olympique de Bamako | In French | → Organizations and associations → Sport, physical exercises | 
| COB | Command Operating Budget | In English | |
| COB | Club Olympique Briochin | In French | → Organizations and associations → Sport, physical exercises | 
| COBA | Cost Benefit Analysis | In French | → Prices | 
| COBAE | Comissão Brasileira de Atividades Espaciais | In Portuguese | → Astronomy → Astronautics → Brazil | 
| COBE | Cosmic Background Explorer | In English | → Astronautics → Astronomy | 
| COBIT | Control OBjectives for Information and related Technology | In English | → Computer science | 
| COBOL | Common Business-Oriented Language | In English | → Programming languages | 
| COBOL | COmmon Business Oriented Language | In English | → Programming languages | 
| CoBos | Contributions from the Bosscha Observervatory | In English | → Serial publications, periodicals → Astronomy | 
| COBRA | Copenhagen, Brussel, Amsterdam | In Dutch | → Geography → Europe | 
| COBRA | Consolidated Omnibus Budget Reconciliation Act | In English | → Labour, labour economics → Medicine | 
| CoBrA | Copenhague, Bruxelles, Amsterdam | In French | → Painting | 
| CoBrn | Contributions of the Public Observatory and Planetarium in Brno | In English | → Serial publications, periodicals → Astronomy | 
| COC | Certificate Of Completion | In English | |
| COC | Chip On Chip | In English | → Electronics | 
| COC | Committee on Curricula | In English | → Education | 
| COCA | Commission on Osteopathic College Accreditation | In English | → Organizations and associations → Medicine | 
| CoCAC | Conseiller de Coopération et d'Action Culturelle | In French | → International relations → Civilization, culture, progress → Arts | 
| CoCam | Contributions from the Cambridge Observatory England | In English | → Serial publications, periodicals → Observatories → Astronomy → United Kingdom | 
| COCEF | Comisión de Cooperación Ecológica Fronteriza = BECC | Border Environment Cooperation Commission | In English = COCEF | Comissão de Cooperação Ecológica Fronteiriça | In Portuguese | In Spanish | → International relations → Environmental protection | 
| COCEF | Comissão de Cooperação Ecológica Fronteiriça = BECC (look above) | In Portuguese | → International relations → Environmental protection | 
| COCO | CCSR Ocean Component Model | In English | → Marine research, oceanography → Meteorology, climatology | 
| COCO | Contractor Owned-Contractor Operated | In English | |
| CoCoi | Comunicações do Observatório Astronómico da Universidade de Coimbra | In Portuguese | → Serial publications, periodicals → Astronomy | 
| CoCom | Control and Computers | In English | → Serial publications, periodicals → Computer science | 
| COCOMO | Constructive Cost Model | In English | → Prices | 
| COD | Center Operations Directorate | In English | |
| COD | Crack Opening Displacement | In English | |
| COD | Complément d'Objet Direct | In French | → Language, linguistics, literature | 
| CoDAO | Contributions from the Dominion Astrophysical Observatory in Victoria | In English | → Serial publications, periodicals → Astronomy | 
| CODATU | COnférence sur le Développement et l'Aménagement des Transports Urbains pour les pays en développement | In French | → Transport and postal services | 
| CoDDO | Communications from the David Dunlap Observatory | In English | → Serial publications, periodicals → Astronomy | 
| CODEC | Comité Départemental d'Examen des Comptes des Organismes de Sécurité Sociale | In French | → Public administration, government → Insurance | 
| CODEFI | Comité Départemental pour le Financement des Entreprises | In French | → Insurance | 
| CODEMA | City of Dublin Energy Management Agency | In English | → Energy economics | 
| CODERPA | Comité Départemental des Retraites et Personnes Agées | In French | → Labour, labour economics → Insurance | 
| CODES | Comisia consultativă interministerială în domeniul egalităţii de şanse între femei şi bărbaţi | In Romanian | → Central administration | 
| CODESRIA | Conseil pour le Développement de la Recherche en Sciences Sociales en Afrique (www.codesria.org) = CODESRIA | Council for the Development of Social Science Research in Africa | In English | In French | → Organizations and associations → Social sciences → Africa | 
| CODESRIA | Council for the Development of Social Science Research in Africa (www.codesria.org) = (look above) | In English | → Organizations and associations → Social sciences → Africa | 
| CODEV | COopération et DÉVeloppement | In French | → Organizations and associations → Development | 
| CODEVI | COmpte pour le DEVeloppement Industriel | In French | → Finance | 
| CODINORM | Côte d'Ivoire Normalisation | In French | → Standardization | 
| CODIR | COmité de DIRection | In French | → Management | 
| CODIS | Centre Opérationnel Départemental d'Incendie et de Secours | In French | → Regional administration → Firefighting → Traumatology → France | 
| CODOP | COmité de Direction Opérationnel | In French | → Management | 
| CoDun | Contributions from the Dunsink Observatory Dublin Ireland | In English | → Serial publications, periodicals → Astronomy → Republic of Ireland | 
| COE | Conseil d'Orientation pour l'Emploi | In French | → Labour, labour economics | 
| COE | Centro Orientamento Educativo | In Italian | → Organizations and associations → Education | 
| COE | Centre d'Orientation et d'Échanges | In French | |
| COF | Construction Of Facilities | In English | |
| COF | Cost Of Facilities | In English | → Prices | 
| COF | Chip On Flex | In English | → Electronics | 
| COFAC | Construction Facility | In English | |
| COFACE | Compagnie Française d'Assurance pour le Commerce Extérieur (www.coface.fr) | In French | → Trade → France | 
| COFDM | Coded Orthogonal Frequency-Division Multiplexing | In English | → Computer science → Telecommunications | 
| CofFEE | Confederation of Flag and Ensign Enthusiasts | In English | → Organizations and associations → Flags, banners | 
| COFI | Checkout and Fault Isolation | In English | |
| COFIPAC | Compagnie Française d'Investissement, de Participation, d'Assistance et de Coopération | In French | → Economics → France | 
| CoFl | Combustion and Flame | In English | → Serial publications, periodicals → Thermodynamics | 
| COFR | Certificate/Certification Of Flight Readiness | In English | → Aeronautics, aircraft → Astronautics | 
| CoFra | Consiglio Nazionale delle Ricerche Italia. Laboratorio di Astrofisica Frascati, Contributi | In Italian | → Serial publications, periodicals → Astronomy → Italia | 
| COFRAC | Comité Français d'Accréditation | In French | → Standardization → Quality management → France | 
| COFRAS | Compagnie Française d'Assistance Spécialisée | In French | → Military affairs → Military engineering → France | 
| COFW | Certificate Of Flight Worthiness | In English | → Aeronautics, aircraft → Astronautics | 
| COG | Centre des Opérations Gaz | In French | → Energy economics | 
| COG | Centre Opérationnel de Groupement | In French | |
| COGAC | COmpagnie Gazière d'Approvisionnement Charbonnier | In French | → Energy economics → Mining → Chemical technology | 
| COGECOM | Compagnie Générale de Communications | In French | → Telecommunications | 
| COGEMA | Compagnie Générale des Matières Nucléaires | In French | → Mining → Nuclear technology | 
| COGEPA | Compagnie Générale de Participation | In French | → Economics | 
| COGETHERM | COmpagnie française pour la coGÉnération THERMique | In French | → Energy economics → Electrical engineering → France | 
| COGITO | Convergence des Outils de Gestion de l'Informatique et Télécoms des Opérateurs | In French | → Computer science → Telecommunications | 
| COGMAN | Center Of Gravity of payload Manifest | In English | → Astronautics | 
| COGS | Cost Of Goods Sold | In English | → Prices | 
| COI | Conflict Of Interest | In English | |
| COI | Commission de l'Océan Indien (www.coi-ioc.org) = IOC | Indian Ocean Commission | In English | In French | → International relations | 
| COI | Comitè Olímpic Internacional (www.olympic.org) = CIO | Comité International Olympique | In French = IOC | International Olympic Committee | In English = МОК | Международен олимпийски комитет | In Bulgarian = MOO | Međunarodni olimpijski odbor | In Bosnian = MOV | Mezinárodní olympijský výbor | In Czech = IOK | Internationales Olympisches Komitee | In German = ΔΟΕ | Διεθνής Ολυμπιακή Επιτροπή | In Greek = IOK | Internacia Olimpika Komitato | In Esperanto = COI | Comité Olímpico Internacional | In Spanish = ROK | Rahvusvaheline Olümpiakomitee | In Estonian = KOK | Kansainvälinen olympiakomitea | In Finnish = COI | Comité Olímpico Internacional | In Galician = MOO | Međunarodni olimpijski odbor | In Croatian = NOB | Nemzetközi Olimpiai Bizottság | In Hungarian = TOK | Tarptautinis olimpinis komitetas | In Lithuanian = IOC | Internationaal Olympisch Comité | In Dutch = IOK | (Den) internasjonale olympiske komité | In Norwegian = MKOI | Międzynarodowy Komitet Olimpijski | In Polish = COI | Comité Olímpico Internacional | In Portuguese = МОК | Международный олимпийский комитет | In Russian = MOK | Međunarodni olimpijski komitet | In Serbo-Croatian = MOV | Medzinárodný olympijský výbor | In Slovak = MOK | Mednarodni olimpijski komite | In Slovenian = МОК | Међународни олимпијски комитет | In Serbian = IOK | Internationella Olympiska Kommitté | In Swedish = МОК | Міжнародний олімпійський комітет | In Ukrainian | In Catalan | → Organizations and associations → Sport, physical exercises | 
| COI | Comité Olímpico Internacional (www.olympic.org) = CIO, IOC, МОК, MOO, MOV, IOK, ΔΟΕ, ROK, KOK, NOB, TOK, MKOI, MOK (look above) | In Spanish | → Organizations and associations → Sport, physical exercises | 
| COI | Comité Olímpico Internacional (www.olympic.org) = CIO, IOC, МОК, MOO, MOV, IOK, ΔΟΕ, ROK, KOK, NOB, TOK, MKOI, MOK (look above) | In Galician | → Organizations and associations → Sport, physical exercises | 
| COI | Comité Olímpico Internacional (www.olympic.org) = CIO, IOC, МОК, MOO, MOV, IOK, ΔΟΕ, ROK, KOK, NOB, TOK, MKOI, MOK (look above) | In Portuguese | → Organizations and associations → Sport, physical exercises | 
| COI | Complément d'Objet Indirect | In French | → Language, linguistics, literature | 
| CoIAP | Contributions de l'Institut d'Astrophysique de Paris | In French | → Serial publications, periodicals → Astronomy → France | 
| COIG | Comité d'Orientation des Investissements Gaz | In French | → Energy economics | 
| COIL | Chemical Oxygen-Iodine Laser | In English | |
| COIM | Checkout Interpreter (Software) Module | In English | → Software | 
| COIN | Collaboration and Interoperability for Networked enterprises | In English | → Software → Networks, communication | 
| COINS | Combat On-line Illegal Numismatic Sales | In English | → Computer-based techniques → Trade → 737 | 
| COIR | Clinical Oral Implants Research | In English | → Serial publications, periodicals → Medicine | 
| COJESKI | Collectif des Organisations des Jeunes Solidaires du Congo-Kinshasa | In French | → Organizations and associations | 
| COJO | Comité d'Organisation des Jeux Olympiques | In French | → Sport, physical exercises |