| CGNR | Compagnie Générale pour la Navigation du Rhin | In French | → Transport and postal services |
| CGPM | Commission Générale des Pêches pour la Méditerranée | In French | → Public administration, government → Fishing, hunting |
| CGPT | Confédération Générale des Travailleurs Paysans | In French | → Organizations and associations → Labour, labour economics → Agricultural sciences |
| CGR | Concentré de Globules Rouges | In French | → Blood and circulatory system |
| CGRP | Concentré de Globules Rouges Phénotypé | In French | → Blood and circulatory system |
| CGTI | Conseil Général des Technologies de l'Information | In French | → Computer science → Telecommunications |
| CHA | Catholic Health Association | In English | → Associations → Roman catholic church → Medicine |
| CHADD | Children and Adults with Attention Deficit/Hyperactivity Disorder | In English | → Psychology → Psychiatry |
| CHAP | Challenge Handshake Authentication Protocol | In English | → Telecommunications |
| CHAR | Club d'Histoire de l'Anesthésie-Réanimation | In French | → Anesthesiology → History |
| CHARMS | Canadian Hemophilia Assessment and Resource Management Information System | In English | → Knowledge management → Blood and circulatory system → Pathology |
| CHARTH | Compagnie Holding d'Applications et de Réalisations Thermiques et Hydrauliques | In French | → Organizations and associations → Energy economics → Mechanical engineering |
| CHATSEA | Challenges of the Agrarian Transition in Southeast Asia | In English | → Agricultural sciences |
| CHAVI | Center for HIV-AIDS Vaccine Immunology | In English | → Research institutes → Immunology and allergy → Infectious diseases |
| CHB | Centre Hépato-Biliaire | In French | → 6163 |
| CHC | Carcinome hépatocellulaire | In French | → Oncology |
| ChEnC | Chemical Engineering Communications | In English | → Serial publications, periodicals → Chemistry → Chemical technology |
| ChEnN | Chemical Engineering News | In English | → Serial publications, periodicals → Chemistry → Chemical technology |
| ChEnS | Chemical Engineering Science | In English | → Serial publications, periodicals → Chemistry → Chemical technology |
| CHG | Centre Hospitalier Général | In French | → Medicine |
| CHI | Centre Hospitalier Intercommunal | In French | → Medicine |
| ChIEJ | Chinese Institute of Engineers Journal | In English | → Serial publications, periodicals → Engineering, technology |
| CHIP | Children's Hospital Informatics Program | In English | → Software → Pediatry |
| CHIR | Chirurgie, Informatique et Robotique | In French | → Computer science → Surgery, orthopaedics, ophthalmology → Mechanical engineering → Electronics |
| ChJA | Chinese Journal of Aeronautics | In English | → Serial publications, periodicals → Spaceflight engineering, astronautics → Aeronautics, aircraft |
| ChJAA | Chinese Journal of Astronomy and Astrophysics | In English | → Serial publications, periodicals → Spaceflight engineering, astronautics → Astronomy |
| ChJSS | Chinese Journal of Space Science | In English | → Serial publications, periodicals → Astronomy → Spaceflight engineering, astronautics |
| CHLA | Canadian Health Libraries Association = ABSC | Association des Bibliothèques de la Santé du Canada | In French |
In English | → Libraries → Associations → Medicine |
| CHMAC | Coopération Homme-Machine pour l'Assistance à la conduite | In French | → Human-computer interaction → Vehicle engineering → Transport and postal services |
| CHR | Centre Hospitalier Régional | In French | → Medicine |
| CHRE | Council for Healthcare Regulatory Excellence | In English | → Medicine |
| CHRU | Centre Hospitalier Régional et Universitaire | In French | → Medicine |
| CHS | Centre Hospitalier Spécialisé | In French | → Medicine |
| ChSAJ | Chinese Society of Astronautics Journal | In English | → Serial publications, periodicals → Astronomy → Spaceflight engineering, astronautics |
| ChSMJ | Chinese Society of Mechanical Engineers Journal | In English | → Serial publications, periodicals → Mechanical engineering |
| ChSST | Chinese Space Science Technology | In English | → Serial publications, periodicals → Astronomy → Spaceflight engineering, astronautics |
| CHTML | Compact HyperText Markup Language | In English | → Programming languages → Telecommunications |
| CHU | Centre Hospitalier Universitaire | In French | → Medicine |
| CHUV | Centre Hospitalier Universitaire Vaudois | In French | → Higher education, universities → Medicine |
| CHUV | Centre Hospitalier Universitaire Vétérinaire | In French | → Higher education, universities → Veterinary medicine |
| CIBT | Conseil International des Bois Tropicaux | In French | → Organizations and associations → Timber and woodworking industry |
| CIC | Centre d'Investigations Cliniques | In French | → Organizations and associations → Pharmacology, toxicology |
| CIC | Chauffage Individuel Centralisé | In French | → Energy economics |
| CIC | Centre d'Investigation Clinique | In French | → Medicine |
| CICF | Confédération des Industries Céramiques de France | In French | → Organizations and associations → 666 |
| CICF | Chambre des Ingénieurs-Conseil de France | In French | → Organizations and associations → Engineering, technology |
| CICOM | Carrefour International de la Communication | In French | → Telecommunications → Transport and postal services |
| CICR | Comitât entèrnacionâl de la Crouèx-Roge (www.icrc.org) = CICR | Comité Internacional de la Cruz Roja | In Spanish = ICRC | International Committee of the Red Cross | In English = CICR | Comité International de la Croix-Rouge | In French = CICV | Comitê Internacional da Cruz Vermelha | In Portuguese = МККК | Международный комитет Красного Креста | In Russian = SSKK | Starptautiskā Sarkanā Krusta Komiteja | In Latvian = CICR | Comitato Internazionale della Croce Rossa | In Italian = ICRC | 적십자 국제 위원회 | In Korean = CICR | Comitè Internacional de la Creu Roja | In Catalan |
[FRP] | → Organizations and associations → Medicine |
| CICR | Comitato Internazionale della Croce Rossa (www.icrc.org) = ICRC, CICV, МККК, SSKK (look above) |
In Italian | → Organizations and associations → Medicine |
| CICR | Comité International de la Croix-Rouge (www.icrc.org) = ICRC, CICV, МККК, SSKK (look above) |
In French | → Organizations and associations → Medicine |
| CICR | Comité Internacional de la Cruz Roja (www.icrc.org) = ICRC, CICV, МККК, SSKK (look above) |
In Spanish | → Organizations and associations → Medicine |
| CICR | Comitè Internacional de la Creu Roja (www.icrc.org) = ICRC, CICV, МККК, SSKK (look above) |
In Catalan | → Organizations and associations → Medicine |
| CICTA | Commission Internationale pour la Conservation des Thonidés de l'Atlantique | In French | → International relations → Nature and society → Fishing, hunting |
| CICV | Comitê Internacional da Cruz Vermelha (www.icrc.org) = CICR, ICRC, МККК, SSKK (look above) |
In Portuguese | → Organizations and associations → Medicine |
| CIDEM | Compagnie Internationale de Développement Minier | In French | → Mining |
| CIDEN | Centre d’Ingénierie Déconstruction et ENvironnement | In French | → Environmental technology, water supply, waste management |
| CIDT | Centre de développement des technologies de l’information | In French | → Computer science → Telecommunications |
| CIE | Cyprus Institute of Energy | In English | → Energy economics |
| CIE | Commission Internationale de l'Éclairage | In French | → Electrical engineering |
| CIE | Communications Interface Equipment | In English | → Human-computer interaction → Telecommunications |
| CIEEMG | Commission Interministérielle d'Étude des Exportations de Matériels de Guerre | In French | → Military engineering |
| CIF | Centre International de Fret | In French | → Transport and postal services |
| CIFA | Committee for Inland Fisheries of Africa | In English | → Organizations and associations → Fishing, hunting |
| CIFTA | Convenção Interamericana contra a Fabricação Ilícita e o Tráfico de Armas de Fogo, Munições, Explosivos, e Outros Materiais Relacionados = CIFTA | Convención Interamericana contra la Fabricación y el Tráfico Ilícitos de Armas de Fuego, Municiones, Explosivos y Otros Materiales Relacionados | In Spanish = CIFTA | Inter-American Convention against the Illicit Manufacturing of and Trafficking in Firearms, Ammunition, Explosives, and Other Related Materials | In English = CIFTA | Convention Interaméricaine contre la Fabrication et le Trafic illicites d'Armes à feu, munitions, explosifs et autres matériels connexes | In French |
In Portuguese | → International relations → Military engineering |
| CIFTA | Convention Interaméricaine contre la Fabrication et le Trafic illicites d'Armes à feu, munitions, explosifs et autres matériels connexes = (look above) |
In French | → International relations → Military engineering |
| CIFTA | Inter-American Convention against the Illicit Manufacturing of and Trafficking in Firearms, Ammunition, Explosives, and Other Related Materials = (look above) |
In English | → International relations → Military engineering |
| CIFTA | Convención Interamericana contra la Fabricación y el Tráfico Ilícitos de Armas de Fuego, Municiones, Explosivos y Otros Materiales Relacionados = (look above) |
In Spanish | → International relations → Military engineering |
| CIG | Centre d’Ingénierie Générale | In French | → Engineering, technology |
| CIG | Communications and Interface Group | In English | → Human-computer interaction → Telecommunications |
| CIGRE | Conférence Internationale des Grands Réseaux Électriques à haute tension | In French | → Organizations and associations → Electrical engineering |
| CIGT | Centre d'Ingénierie et de Gestion du Trafic | In French | → Transport and postal services |
| CIH | Centre d’Ingénierie Hydraulique | In French | → Mechanical engineering |
| CIHEAM | Centre International des Hautes Études Agronomiques Méditerranéennes (www.ciheam.org) | In French | → Research institutes → Agricultural sciences |
| CIHR | Canadian Institutes of Health Research (www.cihr.ca) = IRSC | Instituts de recherche en santé du Canada | In French |
In English | → Research institutes → Biological sciences → Medicine |
| CIID | Commission Internationale pour les Irrigations et le Drainage = ICID | International Commission for Irrigation and Drainage | In English |
In French | → Organizations and associations → 627 → Agricultural sciences |
| CIINB | Commission Interministérielle des Installations Nucléaires de Base | In French | → Organizations and associations → Central administration → Nuclear technology |
| CIM | Computer-Integrated Manufacturing | In English | → Hardware → Electronics |
| CIMA | Centro de Investigación Médica Aplicada | In Spanish | → Medicine |
| CIMAC | Conseil International des Machines à Combustion | In French | → Organizations and associations → Mechanical engineering |
| CIME | Centre Inter-régional des Mouvements d’Énergie | In French | → Energy economics |
| CIMIR | Commission Interministérielle des Matériels d'Imprimerie et de Reprographie | In French | → Central administration → Graphic industries, printing, publishing |
| CIMLS | Cercle Informatique Médicale entre Lesse et Semois | In French | → Organizations and associations → Computer science → Medicine |
| CIMR | Cambridge Institute for Medical Research | In English | → Research institutes → Medicine |
| CIN | Conférence Internationale sur la Nutrition = CIN | Conferencia Internacional sobre Nutrición | In Spanish = ICN | International Conference on Nutrition | In English = CIN | Conferência Internacional sobre Nutrição | In Portuguese |
In French | → Congresses → Nutrition |
| CIN | Conferência Internacional sobre Nutrição = ICN (look above) |
In Portuguese | → Congresses → Nutrition |
| CIN | Conferencia Internacional sobre Nutrición = ICN (look above) |
In Spanish | → Congresses → Nutrition |
| CINP | Collegium Internationale Neuro-Psychopharmacologicum | In Latin | → Pharmacology, toxicology → Neurology |
| CIP | Communications Interface Processor | In English | → Human-computer interaction → Telecommunications |
| CIPN | Centre d’Ingénierie du Parc Nucléaire en exploitation | In French | → Nuclear technology |
| CIPP | Cured-In-Place Piping | In English | → Environmental technology, water supply, waste management |
| CIPR | Commission Internationale de Protection Radiologique | In French | → Nuclear technology |
| CIPREL | Compagnie Ivoirienne de PRoduction d’ÉLectricité | In French | → Electrical engineering |
| CIRA | Contrôle Industriel et Régulation Automatique | In French | → Specialized or (poly)technical colleges → Mechanical engineering |
| CIRAD | Centre de coopération internationale en recherche agronomique pour le développement | In French | → Biological sciences → Zoology → Agricultural sciences |
| CIRASTI | Collectif Interassociatif pour la Réalisation d'Activités Scientifiques et Techniques Internationales | In French | → International relations → Engineering, technology |
| CIRCE | Confusion-limited Infrared Cosmology Explorer | In English | → Cosmology → Spaceflight engineering, astronautics |
| CIRED | Centre International de Recherches sur l'Environnement et le Développement | In French | → Research institutes → Nature → Agricultural sciences |
| CIRIA | Construction Industry Research and Information Association | In English | → Organizations and associations → Building |
| CIRIMAT | Centre Interuniversitaire de Recherche et d’Ingénierie des Matériaux | In French | → 620 |
| CIRM | California Institute for Regenerative Medicine | In English | → Biotechnology → Medicine |
| CIRRIS | Cryogenic Infrared Radiance Instrumentation for Shuttle | In English | → Spaceflight engineering, astronautics |
| CIRRIS | Cryogenic Infrared Radiance Instrument for Shuttle | In English | → Spaceflight engineering, astronautics |
| CIRSE | Cardiovascular and Interventional Radiological Society of Europe | In English | → Cardiology |
| CIRT | Compagnie Internationale de Radiodiffusion et de la Télévision | In French | → Telecommunications |
| CIS | Centre d'Information sur la Surdité | In French | → Libraries → Pathology |
| CIS | Contact Image Sensor | In English | → Electronics |
| CIS | Community Innovation Survey | In English | → Engineering, technology |
| CISI | Comité Interministériel pour la Société de l'Information | In French | → Central administration → Computer science → Telecommunications |
| CISMA | Conférence Internationale sur le Sida et les Maladies sexuellement transmissibles en Afrique | In French | → Organizations and associations → Infectious diseases |
| CISMeF | Catalogage et Indexation des Sites Médicaux Francophones | In French | → Libraries → Medicine |
| CISR | Comité Interministériel de Sécurité Routière | In French | → Central administration → Transport and postal services |
| CISR | Comité Interministériel de la Sécurité Routière | In French | → Central administration → Telecommunications |
| CIT | Centro de Información Tecnológica | In Spanish | → Libraries → Engineering, technology |
| CIT | California Institute of Technology | In English | → Engineering, technology |
| CIT | Centre d'Ingénierie Thermique | In French | → Energy economics |
| CITEL | Comissão Interamericana de Telecomunicações = CITEL | Comisión Interamericana de Telecomunicaciones | In Spanish = CITEL | Commission Interaméricaine des Télécommunications | In French |
In Portuguese | → Organizations and associations → Telecommunications |
| CITEL | Commission Interaméricaine des Télécommunications = (look above) |
In French | → Organizations and associations → Telecommunications |
| CITEL | Comisión Interamericana de Telecomunicaciones = (look above) |
In Spanish | → Organizations and associations → Telecommunications |
| CITI | Centre d’Innovation en Télécommunications et Intégration de services | In French | → Research institutes → Telecommunications |
| CITIC | Centro Andaluz de Innovación y Tecnologías de la Información y las Comunicaciones (www.citic.es) | In Spanish | → Research institutes → Computer science → Telecommunications |
| CITILOG | Carrefour Intelligent - Traitement d'Images LOGiciels | In French | → Image processing → Transport and postal services |
| CITM | Chubu Institute of Technology, Memoirs | In English | → Serial publications, periodicals |
| CITS | Croatian Information Technology Society | In English | → Organizations and associations → Computer science → Telecommunications |
| CIU | Communication Interface Unit | In English | → Human-computer interaction → Telecommunications |
| CIUMR | Commission Internationale des Unités et des Mesures de Radiation = ICRU | International Commission on Radiation Units and Measurements | In English = CIUMR | Comisión Internacional de Unidades y Medidas Radiológicas | In Spanish = CIUMR | Comissão Internacional de Unidades e Medidas Radiação | In Portuguese |
In French | → Standardization → Nuclear technology |
| CIUMR | Comisión Internacional de Unidades y Medidas Radiológicas = ICRU (look above) |
In Spanish | → Standardization → Nuclear technology |
| CIUMR | Comissão Internacional de Unidades e Medidas Radiação = ICRU (look above) |
In Portuguese | → Standardization → Nuclear technology |
| CIVAM | Centre d’Initiative pour Valoriser l’Agriculture et le Milieu rural | In French | → Organizations and associations → Agricultural sciences |
| CIVD | Coagulation Intravasculaire Disséminée | In French | → Blood and circulatory system |
| CJChE | Canadian Journal of Chemical Engineering | In English | → Serial publications, periodicals → Chemical technology → Chemistry |
| CJE | Compteur Jaune Électronique | In French | → Electrical engineering |
| CJECE | Canadian Journal of Electrical Computer Engineering | In English | → Serial publications, periodicals → Computer science → Electrical engineering |
| CJK | Creutzfeldt-Jakob-Krankheit | In German | → Neurology |
| CJPP | Canadian Journal of Physiology and Pharmacology | In English | → Serial publications, periodicals → Physiology → Pharmacology, toxicology |
| CLAP | Centro Latinoamericano de Perinatología y Desarrollo Humano (www.clap.ops-oms.org) = CLAP | Centro Latino-Americano de Perinatologia e Desenvolvimento Humano | In Portuguese |
In Spanish | → Gynaecology, obstetrics → Pediatry |
| CLAP | Centro Latino-Americano de Perinatologia e Desenvolvimento Humano (www.clap.ops-oms.org) = (look above) |
In Portuguese | → Gynaecology, obstetrics → Pediatry |
| CLCC | Centres de Lutte Contre le Cancer | In French | → Oncology |
| CLDB | Cell Line Data Base | In English | → Cytology → Biotechnology |
| CLE | Compteur Libre Énergie | In French | → Energy economics → Electrical engineering |
| CLER | Comité de Liaison Énergies Renouvelables | In French | → Energy economics |
| CLIN | Comité de Lutte contre l'Infection Nosocomiale | In French | → Organizations and associations → Infectious diseases |
| CLIP | Calling Number Identification Presentation | In English | → Telecommunications |
| CLIR | Calling Number Identification Restriction | In English | → Telecommunications |
| CLM | Circumlunar Mission | In English | → Spaceflight engineering, astronautics |
| CLOT | Combined Loads Orbiter Test | In English | → Spaceflight engineering, astronautics |
| CLS | Contingency Landing Site | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| CLS | Collecte Localisation Satellites | In English | → Spaceflight engineering, astronautics → Earth sciences |
| CLSO | Contingency Landing Support Officer | In English | → 692973 → Spaceflight engineering, astronautics |
| CLUD | Comité de Lutte contre La Douleur | In French | → Organizations and associations → Medicine |
| CM | Cervical Mucous | In English | → Gynaecology |
| CMA | Compagnie Maritime d'Affrètement | In French | → 6295 → Transport and postal services |
| CMAG | Cruise Missile Advanced Guidance | In English | → Military engineering |
| CMAME | Computer Methods in Applied Mechanics and Engineering | In English | → Serial publications, periodicals → Computer science → 531 → Mechanical engineering |
| CMB | Colegiul Medicilor din Bucuresti | In Romanian | → Medicine |
| CMC | Chemistry, Manufacturing, and Controls | In English | → Pharmacology, toxicology → Chemical technology |
| CMDR | Colegiul Medicilor Dentisti din România | In Romanian | → Dentistry |
| CME | Consiliul Mondial al Energiei = CME | Conseil Mondial de l'Énergie | In French = WEC | World Energy Council | In English |
In Romanian | → Organizations and associations → International relations → Energy economics |
| CME | Conseil Mondial de l'Énergie = WEC (look above) |
In French | → Organizations and associations → International relations → Energy economics |
| CME | Congrès Mondial de l’Énergie | In French | → Congresses → Energy economics |
| CMIE | Centre Médical Interentreprises Europe | In French | → Labour, labour economics → Medicine |
| CMIP | Centre Médical de l'Institut Pasteur | In French | → Medicine |
| CMM | Centre for Molecular Medicine | In English | → Research institutes → Medicine |
| CMM | Center for Molecular Medicine | In English | → Research institutes → Biochemistry, biophysics → Medicine |
| CMMIC | Compagnie Minière et Métallurgique de l’Indo-Chine | In French | → Mining → Metallurgy |
| CMO | Chief Marketing Officer | In English | → 659 |
| CMOI | Contrôles et Mesures Optiques pour l’Industrie | In French | → Engineering, technology |
| CMOI | Contrôles et Mesures Optiques pour l'Industrie | In French | → Optics |
| CMOS | Complementary Metal Oxide Semiconductor | In English | → Electronics |
| CmpEn | Composites Engineering | In English | → Serial publications, periodicals → 620 |
| CmpMa | Composites Manufacturing | In English | → Serial publications, periodicals → 620 |
| CMPP | Centre médico-psycho-pédagogique | In French | → Psychology → Education → Medicine |
| CmpSt | Composite Structures | In English | → Serial publications, periodicals → 620 |
| CMR | Colegiul Medicilor din România | In Romanian | → Organizations and associations → Medicine |
| CMS | Centers for Medicare and Medicaid Services | In English | → Medicine |
| CMS | Composants à Montage de Surface | In French | → Electronics |
| CMSA | Caisse de Mutualité Sociale Agricole | In French | → Insurance → Agricultural sciences |
| CMSRSC | Maritime Silk Roads Study Centre | In English | → Research institutes → Transport and postal services |
| CMV | Cytomegalovirus | In German | → Virology → Pathology |
| CMVR | Colegiul Medicilor Veterinari din România | In Romanian | → Organizations and associations → Veterinary medicine |
| CNA | Caisse Nationale des Autoroutes | In French | → Civil engineering → Transport and postal services |
| CNAE | Comissão Nacional de Atividades Espaciais | In Portuguese | → Astronomy → Spaceflight engineering, astronautics |
| CNAFMC | Caisse Nationale d'Allocations Familiales des Marins du Commerce | In French | → Social welfare → Transport and postal services |
| CNAFNI | Caisse Nationale d'Allocations Familiales de la Navigation Intérieure | In French | → Social welfare → Transport and postal services |
| CNAFPM | Caisse Nationale d'Allocations Familiales de la Pêche Maritime | In French | → Social welfare → Fishing, hunting |
| CNAM | Conservatoire National des Arts et Métiers | In French | → Specialized or (poly)technical colleges |
| CNAS | Casa Naţională de Asigurări de Sănătate | In Romanian | → Public administration, government → Medicine |
| CNASEA | Centre National pour l'Aménagement des Structures des Exploitations Agricoles | In French | → Organizations and associations → Agricultural sciences |
| CNBA | Chambre Nationale de la Batellerie Artisanale | In French | → Organizations and associations → Transport and postal services |
| CNBM | Confédération du Négoce de Bois et Matériaux | In French | → Organizations and associations → Trade → Timber and woodworking industry |
| CNC | Compagnie Nouvelle de Conteneurs | In French | → Transport and postal services |
| CNC | Commande Numérique par Calculateur | In French | → Engineering, technology |
| CNC | Comité National de la Conchyliculture (www.cnc-france.com) | In French | → Fishing, hunting → Food technology |
| CNC | Conseil National de la Comptabilité | In French | → Organizations and associations → Accounting |
| CNCA | Caisse Nationale de Crédit Agricole | In French | → Banks → Agricultural sciences |
| CNCBD | China National Center for Biotechnology Development | In English | → Biotechnology |
| CNCL | Commission Nationale de la Communication et des Libertés | In French | → Telecommunications → Politics |
| CNDB | Centre National pour le Développement du Bois | In French | → Organizations and associations → Forestry |
| CNDCA | Comité National de Défense contre l'Alcoolisme | In French | → Organizations and associations → Medicine |
| CNDRI | Contrôle Non Destructif par Rayonnements Ionisants | In French | → Mechanical engineering |
| CNEA | Comisión Nacional de Energía Atómica (www.cnea.gov.ar) | In Spanish | → Central administration → Nuclear technology |