| CIPSG | Canadian Information Processing Society Graphics Interface | In English | → Serial publications, periodicals |
| CIPUF | Carrefour International de la Presse Universitaire Francophone (www.cipuf.org) | In French | → Organizations and associations → Newspapers, journalism → Higher education, universities |
| CIR | Crédit d'Impôt Recherche | In French | → Research policy → Taxes, duties |
| CIRDN | Comité Interamericano para la Reducción de los Desastres Naturales = IACNDR | Inter-American Committee on Natural Disaster Reduction | In English = CIRDN | Comitê Interamericano sobre a Redução de Desastres Naturais | In Portuguese |
In Spanish | → Organizations and associations → Natural disasters |
| CIRDN | Comitê Interamericano sobre a Redução de Desastres Naturais = IACNDR (look above) |
In Portuguese | → Organizations and associations → Natural disasters |
| CIRED | Centre International de Recherches sur l'Environnement et le Développement | In French | → Research institutes → Nature → Agricultural sciences |
| CIRESS | Centre Interdisciplinaire de Recherches et d'Études sur les Systèmes Sociaux | In French | → Organizations and associations → Social sciences |
| CIRESS | Colloque International sur les Ressources en Eau Souterraines dans le Sahara | In French | → Congresses → Hydrology |
| CIRHAC | Centre Inter-universitaire de Recherche en Histoire de l’Art Contemporain | In French | → Research institutes → History |
| CIRIA | Construction Industry Research and Information Association | In English | → Organizations and associations → Building |
| CIRIEC | Centre International de Recherches et d'Information sur l'Économie Publique, Sociale et Coopérative = IFIG | Internationales Forschungs- und Informationszentrum für öffentliche Wirtschaft, Sozialwirtschaft und Genossenschaftswesen | In German |
In French | → Organizations and associations → Economics |
| CIRIT | Comissió Interdepartemental de Recreca i Innovació Tecnològica | In Spanish | → Public administration, government → Research policy |
| CIRST | Comité Interministériel de la Recherche Scientifique et Technique | In French | → Central administration → Research policy |
| CIS | Centre d'Information sur la Surdité | In French | → Libraries → Pathology |
| CIS | Commissione Italiana di Stratigrafia | In Italian | → Organizations and associations → Earth sciences |
| CIS | Communication Interface System | In English | → Human-computer interaction |
| CISAL | Confederazione Italiana Sindacati Autonomi Lavoratori | In Italian | → Organizations and associations → Labour, labour economics |
| CISAS | Confederazione Italiana Sindicati Addetti ai Servizi | In Italian | → Organizations and associations → Labour, labour economics |
| CISC | Complex Instruction Set Computer | In English | → Hardware |
| CISI | Comité Interministériel pour la Société de l'Information | In French | → Central administration → Computer science → Telecommunications |
| CISI | Compagnie Internationale de Services en Informatique | In French | → Computer science |
| CISL | Confédération Internationale des Syndicats Libres (www.icftu.org) = ICFTU | International Confederation of Free Trade Unions | In English = CIOSL | Confederación Internacional de Organizaciones Sindicales Libres | In Spanish = CIOSL | Confederação Internacional de Organizações Sindicais Livres | In Portuguese = ICB | International Criminal Bar | In English = BPI | Barreau Pénal International | In French |
In French | → Organizations and associations → Labour, labour economics |
| CISL | Confederazione Italiana Sindacati Lavoratori | In Italian | → Organizations and associations → Labour, labour economics |
| CISM | Conseil International du Sport Militaire | In French | → Organizations and associations → 355 → Sport, physical exercises |
| 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 |
| CISO | Chief Information Security Officer = RSSI | Responsable de la Sécurité des Systèmes d'Information | In French |
In English | → Computer science |
| CISP | Comitato Internazionale per lo Sviluppo dei Popoli | In Italian | → Organizations and associations |
| CISPEL | Confederazione Italiana dei Servizi Pubblici degli Enti Locali | In Italian | → Organizations and associations → Municipal administration |
| CISS | Cooperazione Internazionale Sud-Sud | In Italian | → Organizations and associations |
| CISS | Conferencia Interamericana de Seguridad Social | In Spanish | → Organizations and associations → Insurance |
| CiSSV | Circolare Interna della Sezione Stelle Variabili dell'Unione Astrofili Italiani | In Italian | → Serial publications, periodicals → Astronomy |
| CIST | Centre d'Information sur les Sciences de la Terre | In French | → Libraries → Earth sciences |
| CISV | Centro Italiano Studi Vessillologici (www.cisv.it) | In Italian | → 9299 |
| CISV | Comunità Impegno Servizio Volontariato | In Italian | → Organizations and associations |
| CIT | Centro de Información Tecnológica | In Spanish | → Libraries → Engineering, technology |
| 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 | Comisión Interamericana de Telecomunicaciones = (look above) |
In Spanish | → Organizations and associations → Telecommunications |
| CITEL | Commission Interaméricaine des Télécommunications = (look above) |
In French | → Organizations and associations → Telecommunications |
| CITHER | Consultation en Texte Intégral des THèses en Réseau | In French | → Knowledge management → Higher education, universities → Mathematics and natural sciences |
| 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 | Centre de la Imatge i Tecnologia Multimèdia (www.citm.upc.edu) | In Spanish | → Image processing → Cinema, movies |
| CITM | Chubu Institute of Technology, Memoirs | In English | → Serial publications, periodicals → Applied sciences, technology |
| CITS | Croatian Information Technology Society | In English | → Organizations and associations → Computer science → Telecommunications |
| CIU | Club International Universitaire | In French | → Organizations and associations → Higher education, universities |
| CIU | Communication Interface Unit | In English | → Human-computer interaction → Telecommunications |
| CIU | Computer Interface Unit | In English | → Human-computer interaction |
| CIU | Controller Interface Unit | In English | → Human-computer interaction |
| CIU | Comitato Italiano per l'UNICEF | In Italian | → Organizations and associations |
| CIU | Consorzio Interprovinciale Universitario | In Italian | → Organizations and associations → Higher education, universities |
| CIUMR | Comisión Internacional de Unidades y Medidas Radiológicas = ICRU | International Commission on Radiation Units and Measurements | In English = CIUMR | Commission Internationale des Unités et des Mesures de Radiation | In French = CIUMR | Comissão Internacional de Unidades e Medidas Radiação | In Portuguese |
In Spanish | → Standardization → Nuclear technology |
| CIUMR | Commission Internationale des Unités et des Mesures de Radiation = ICRU (look above) |
In French | → Standardization → Nuclear technology |
| CIUMR | Comissão Internacional de Unidades e Medidas Radiação = ICRU (look above) |
In Portuguese | → Standardization → Nuclear technology |
| CiUO | Circular of the Union Observatory Johannesburg | In English | → Serial publications, periodicals → Astronomy |
| CIVAM | Centre d’Initiative pour Valoriser l’Agriculture et le Milieu rural | In French | → Organizations and associations → Agricultural sciences |
| CJA | Christlich-Jüdische Arbeitsgemeinschaft Basel | In German | → Associations → Judaism → Christianity |
| CJAS | Copenhagen Journal of Asian Studies | In English | → Serial publications, periodicals → Language, linguistics, literature → Geography, biography, history |
| CJChE | Canadian Journal of Chemical Engineering | In English | → Serial publications, periodicals → Chemical technology → Chemistry |
| CJD | Centre des Jeunes Dirigeants d'Entreprises | In French | → Organizations and associations → Economics |
| ĈJEA | 中国における青年エスペラント団体です = ĈJEA | Ĉina Junulara Esperanto-Asocio | In Esperanto |
In Japanese | → Organizations and associations |
| ĈJEA | Ĉina Junulara Esperanto-Asocio = (look above) |
In Esperanto | → Associations |
| CJECE | Canadian Journal of Electrical Computer Engineering | In English | → Serial publications, periodicals → Computer science → Electrical engineering |
| CJKI | (The) Chinese, Japanese, and Korean Dictionary Institute | In English | → Dictionaries → Linguistics |
| CJLTP | Chinese Journal of Low Temperature Physics | In English | → Serial publications, periodicals → Physics |
| CJMat | Canadian Journal of Mathematics | In English | → Serial publications, periodicals → Mathematics |
| CJNE | Canadian Journal of Native Education | In English | → Serial publications, periodicals → Education |
| CJPP | Canadian Journal of Physiology and Pharmacology | In English | → Serial publications, periodicals → Physiology → Pharmacology, toxicology |
| CJSA | China Judaic Studies Association | In English | → Associations → Judaism → Language, linguistics, literature → Geography, biography, history |
| CJV | Christelijke Jongeren Vereniging | In Dutch | → Organizations and associations → Christianity |
| CJVV | Christelijke Jongelieden Voetbal Vereniging | In Dutch | → Organizations and associations → Christianity → Football and rugby |
| CKC | Capelle Kralingscheveer Combinatie | In Dutch | → Organizations and associations → Sport, physical exercises |
| CLA | Cantonese Language Association (http://asiane.byu.edu/cla/) | In English | → Associations → Education → Language, linguistics, literature |
| CLAAI | Confederazione delle Libere Associazioni Artigiane Italiane | In Italian | → Organizations and associations |
| CLADES | Centro Latinoamericano de Documentación Económica y Social = CLADES | Centre Latino-américain de Documentation Économique et Sociale | In French = CLADES | Centro Latino-americano de Documentação Econômica e Social | In Portuguese |
In Spanish | → Libraries → Social sciences → Economics |
| CLADES | Centro Latino-americano de Documentação Econômica e Social = (look above) |
In Portuguese | → Libraries → Social sciences → Economics |
| CLADES | Centre Latino-américain de Documentation Économique et Sociale = (look above) |
In French | → Libraries → Social sciences → Economics |
| CLAEH | Centro Latino-Americano de Economía Humana (www.claeh.org.uy) = CLAEH | Centre Latino-Américain d'Économie Humaine | In French = CLAEH | Centro Latino-americano de Economia Humana | In Portuguese |
In Spanish | → Research institutes → Economics |
| CLAEH | Centre Latino-Américain d'Économie Humaine (www.claeh.org.uy) = (look above) |
In French | → Research institutes → Economics |
| CLAEH | Centro Latino-americano de Economia Humana (www.claeh.org.uy) = (look above) |
In Portuguese | → Research institutes → Economics |
| CLAH | Conference on Latin American History | In English | → Organizations and associations → History |
| CLARA | Cooperación Latino Americana de Redes Avanzadas | In Spanish | → Networks, communication |
| CLASS | Chinese Language Association for Secondary-Elementary Schools | In English | → Associations → Education → Linguistics |
| CLASS | Chinese Language Association for Secondary School (www.classk12.org) | In English | → Associations → Education → Language, linguistics, literature |
| CLC | Canadian Labour Congress = CTC | Congrès du Travail du Canada | In French |
In English | → Organizations and associations → Labour, labour economics |
| ClDy | Climate Dynamics | In English | → Serial publications, periodicals → Meteorology, climatology |
| CLE | Comité Local d'Experts | In French | → Organizations and associations |
| CLEV | Culture, Loisirs, Entraide, Voyages | In French | → Organizations and associations |
| CLGE | Comité de Liaison des Géomètres Européens | In French | → Organizations and associations → Geodesy, cartography |
| CLGE | Council of European Geodetic Surveyors | In English | → Organizations and associations → Geodesy, cartography |
| CLGE | Central Laboratory of General Ecology | In English | → Research institutes → Ecology |
| CLIN | Comité de Lutte contre l'Infection Nosocomiale | In French | → Organizations and associations → Infectious diseases |
| CliPa | Climate of the Past | In English | → Serial publications, periodicals → Meteorology, climatology |
| CliPD | Climate of the Past Discussions | In English | → Serial publications, periodicals → Meteorology, climatology |
| CLIPS | Communication Langagière et Interaction Personne-Système | In French | → Human-computer interaction → Linguistics |
| CLMC | Comunità Laici Missionari Cattolici | In Italian | → Organizations and associations → Roman catholic church |
| CLMC | Central Logistics Management Center | In English | → Maintenance and logistics |
| CLO | Club Linux Outaouais | In French | → Organizations and associations → Operating systems |
| CLORA | CLub des Organismes de Recherche Associés | In French | → Organizations and associations → Research policy |
| CLPCF | Centre de Lecture Publique de la Communauté Française | In French | → Libraries |
| CLS | Computational Life Sciences | In English | → Computer-based techniques → Biological sciences |
| CLS | Cable Library System | In English | → Hardware → Libraries |
| CLSJ | The Chinese Linguistic Society of Japan | In English | → Organizations and associations → Linguistics |
| CLTA | Chinese Language Teachers' Association | In English | → Associations → Education → Language, linguistics, literature |
| CLTA | Chinese Language Teachers Association (http://clta-us.org) | In English | → Associations → Education → Language, linguistics, literature |
| CLTA-GNY | Chinese Language Teachers' Association of Greater New York | In English | → Associations → Language, linguistics, literature |
| CLTASA | Chinese Language Teachers' Association of South Australia | In English | → Associations → Education → Language, linguistics, literature |
| CLTAV | Chinese Language Teachers' Association of Victoria | In English | → Associations → Education → Language, linguistics, literature |
| CLTFA | Chinese Language Teachers' Federation of Australia | In English | → Organizations and associations → Education → Language, linguistics, literature |
| CLUD | Comité de Lutte contre La Douleur | In French | → Organizations and associations → Medicine |
| CLUW | Coalition of Labor Union Women | In English | → Organizations and associations → Labour, labour economics → Feminism |
| CM | Change Management | In English | → Management |
| CMAME | Computer Methods in Applied Mechanics and Engineering | In English | → Serial publications, periodicals → Computer science → 531 → Mechanical engineering |
| CMB | Compagnie des Machines Bull | In French | → Hardware |
| CMC | Centraal Missie Commissariaat | In Dutch | → Organizations and associations → Development |
| CMC | Central Maintenance Computer | In English | → Hardware → Maintenance and logistics |
| CMCS | Centralized Maintenance Computer System | In English | → Software → Maintenance and logistics |
| CMDB | Configuration Management Date Base | In English | → Hardware |
| CMDRG | Cislennye Metody v Dinamike Razrežennyh Gazov | In Russian | → Serial publications, periodicals → Physics |
| CME | Conseil Mondial de l'Énergie = CME | Consiliul Mondial al Energiei | In Romanian = WEC | World Energy Council | In English |
In French | → Organizations and associations → International relations → Energy economics |
| CME | Consiliul Mondial al Energiei = WEC (look above) |
In Romanian | → Organizations and associations → International relations → Energy economics |
| CME | Congrès Mondial de l’Énergie | In French | → Congresses → Energy economics |
| CMEAS | Consortium for Middle Eastern and African Studies | In English | → Organizations and associations → Language, linguistics, literature → Geography, biography, history |
| CMHS | Chinese Military History Society | In English | → Organizations and associations → History |
| CMI | Caucasus Media Institute | In English | → Newspapers, journalism |
| CMIP | Common Management Information Protocol | In English | → Networks, communication |
| CMIRH | Centre Mondial Informatique et Ressources Humaines | In French | → Management → Personnel management |
| CML | Chemical Markup Language | In English | → Programming languages → Chemistry |
| CMM | Centre for Molecular Medicine | In English | → Research institutes → Medicine |
| CMM | Condition-Monitored Maintenance | In English | → Maintenance and logistics |
| CMM | Center for Molecular Medicine | In English | → Research institutes → Biochemistry, biophysics → Medicine |
| CMMI | Capability Maturity Model Integration | In English | → Computer science |
| CMMPh | Computational Mathematics and Mathematical Physics | In English | → Serial publications, periodicals → Mathematics → Physics |
| CmpEn | Composites Engineering | In English | → Serial publications, periodicals → 620 |
| CmpMa | Composites Manufacturing | In English | → Serial publications, periodicals → 620 |
| CmpSt | Composite Structures | In English | → Serial publications, periodicals → 620 |
| CMR | China Media Research | In English | → Newspapers, journalism |
| CMR | Colegiul Medicilor din România | In Romanian | → Organizations and associations → Medicine |
| CMS | Content Management System = SGC | Système de Gestion de Contenu(s) | In French |
In English | → Document processing → Knowledge management |
| CMS | Content Management Server | In English | → Networks, communication → Document processing → Knowledge management |
| CMSI | Command Monitor System Interface | In English | → Human-computer interaction |
| CMSP | Caucasus Media Support Project | In English | → Newspapers, journalism |
| CMSR | Centro Mondialità Sviluppo Reciproco | In Italian | → Organizations and associations → Development |
| CMSRSC | Maritime Silk Roads Study Centre | In English | → Research institutes → Transport and postal services |
| CMT | Continuum Mechanics and Thermodynamics | In English | → Serial publications, periodicals → 531 → Thermodynamics |
| CMTS | Computerized Maintenance Test System | In English | → Computer science → Maintenance and logistics |
| CMVR | Colegiul Medicilor Veterinari din România | In Romanian | → Organizations and associations → Veterinary medicine |
| CMwA | Computers and Mathematics with Applications | In English | → Serial publications, periodicals → Computer science → Mathematics |
| CMWCI | Contributions from the Mount Wilson Observatory / Carnegie Institution of Washington | In English | → Serial publications, periodicals → Astronomy |
| CNA | Confederazione Nazionale dell'Artigianato e della Piccola e Media Impresa | In Italian | → Organizations and associations |
| CNAC | Centre National d'Art et de Culture | In French | → Civilization, culture, progress → Arts |
| 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 | Conseil National du Commerce | In French | → Organizations and associations → Trade |
| CNC | Conseil National de la Comptabilité | In French | → Organizations and associations → Accounting |
| CNC | Conseil National de la Communication | In French | → Organizations and associations → 359 |
| CNC | Computer Numerical Control | In English | → Computer science |
| CNC | Computer Numerically Controlled | In English | → Computer science |
| CNCSIS | Consiliu Naţional al Cercetării Ştiinţifice din Învăţământul Superior | In Romanian | → Organizations and associations → Research policy |
| CNCSIS | Consiliul National al Cercetarii Stiintifice din Învatamântul Superior | In Romanian | → Research policy → Higher education, universities |
| CND | China News Digest | In English | → Newspapers, journalism |
| 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 |
| CNDL | Conference of Directors of National Libraries | In English | → Organizations and associations → Libraries |
| CNDP | Centre National de Documentation Pédagogique | In French | → Libraries → Education |
| CNEI | Centre National d'Études Informatiques | In French | → Computer science |
| CNER | Comité National d'Évaluation de la Recherche | In French | → Research policy |
| CNFK | Campus Numérique Francophone de Kinshasa | In French | → Networks, communication |
| CNFM | Comité National Français de la Mécanique | In French | → Organizations and associations → Mechanical engineering |
| CNG | Centre National de Génotypage (www.cng.fr) | In French | → Research institutes → Genetics |
| CNHI | Cité Nationale de l'Histoire de l'Immigration | In French | → Museums → Migrations |
| CNHIM | Centre National Hospitalier d'Information sur le Médicament | In French | → Organizations and associations → Pharmacology, toxicology |
| ČNI | Český Normalizační Institut | In Czech | → Standardization |
| CNI | Coalition for Networked Information | In English | → Organizations and associations → Libraries |
| CNIC | Commission Nationale d'Interprétation et de Conciliation | In French | → Organizations and associations → Law, jurisprudence |
| CNIG | Centro de Documentação e Informação | In Portuguese | → Libraries |
| CNII | Centre National d’Ingénierie de l’Information | In French | → Computer science |
| CNIL | Commission Nationale Informatique et Libertés | In French | → Organizations and associations → Computer science → Fundamental rights |
| CNIL | Commission Nationale de l'Informatique et des Libertés (www.cnil.fr) | In French | → Computer science → Politics |
| CNIM | Comitato Nazionale Italiano per la Manutenzione | In Italian | → Organizations and associations |
| CNIPMMR | Consiliul Naţional al Întreprinderilor Private Mici şi Mijlocii din România | In Romanian | → Organizations and associations |
| CNL | Confédération Nationale du Logement | In French | → Organizations and associations → Accommodation |
| CNMCCA | Confédération Nationale de la Mutualité, de la Coopération et du Crédit Agricole | In French | → Organizations and associations → Insurance → Agricultural sciences |
| CNME | Communications in Numerical Methods in Engineering | In English | → Serial publications, periodicals → Mathematics → Engineering, technology |
| CNNMN | Commision on New Minerals and Mineral Names | In English | → Organizations and associations → Mineralogy → Petrology |
| CNP | Confédération Nationale Paysanne | In English | → Organizations and associations → Agricultural sciences → History |
| CNPEJ | Commission Nationale Paritaire de l'Emploi des Journalistes | In French | → Newspapers, journalism → Labour, labour economics |
| CNPF | Conseil National du Patronat Français | In French | → Organizations and associations → Labour, labour economics |
| CNPL | Conselho Nacional das Profissões Liberais | In Portuguese | → Organizations and associations |
| CNPL | Conselho Nacional de Profissões Liberais | In Portuguese | → Organizations and associations |
| CNPL | Canadian National Poker League | In English | → Organizations and associations → Entertainment |
| CNPL | Chambre Nationale des Professions libérales | In French | → Organizations and associations |
| CNPL | Confederação Nacional das Profissões Liberais | In Portuguese | → Organizations and associations |
| CNPR | Confederaţia Naţională a Patronatului Român | In Romanian | → Organizations and associations → Labour, labour economics |
| CNR | Consiglio Nazionale delle Ricerche | In Italian | → Research policy |
| CNRA | Conseil National des Radios Associatives | In French | → Organizations and associations → Telecommunications |
| CNRL | Communications and Navigation Research Laboratory | In English | → Research institutes → Telecommunications |
| CNRS | Centre National de la Recherche Scientifique | In French | → Research policy → Mathematics and natural sciences |