| CLM | Care Logic Module | In English | |
| CLM | Circumlunar Mission | In English | → Spaceflight engineering, astronautics |
| CLMC | Central Logistics Management Center | In English | → Maintenance and logistics |
| CLOT | Combined Loads Orbiter Test | In English | → Spaceflight engineering, astronautics |
| CLOUDSAT | Cloud Cover Statistical Analysis Program | In English | |
| CLPB | Chinese Law Prof Blog | In English | → Law, jurisprudence |
| CLRAE | Congress of Local and Regional Authorities of Europe | In English | → European Union |
| CLRB | Cost Limit Review Board | In English | → Prices |
| CLS | Contingency Landing Site | In English | → Aeronautics, aircraft → Spaceflight engineering, astronautics |
| CLS | Collecte Localisation Satellites | In English | → Spaceflight engineering, astronautics → Earth sciences |
| CLS | Cable Library System | In English | → Hardware → Libraries |
| CLS | Computational Life Sciences | In English | → Computer-based techniques → Biological sciences |
| CLSJ | The Chinese Linguistic Society of Japan | In English | → Organizations and associations → Linguistics |
| CLSM | Confocal Laser Scanning Microscope/Microscopy = MCBL | Microscope/Microscopie confocal(e) à balayage laser | In French |
In English | → Physics |
| CLSO | Contingency Landing Support Officer | In English | → 692973 → Spaceflight engineering, astronautics |
| 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 |
| CLTAD | Centre for Learning & Teaching in Art & Design | In English | → Education → Arts |
| 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 |
| CLUW | Coalition of Labor Union Women | In English | → Organizations and associations → Labour, labour economics → Feminism |
| CM | Cervical Mucous | In English | → Gynaecology |
| CM | Control Mode | In English | |
| CM | Consumable Management | In English | |
| CM | Configuration Monitor | In English | |
| CM | Configuration Management | In English | |
| CM | Command Module | In English | |
| CM | Change Management | In English | → Management |
| CM | Center of Mass | In English | |
| CM | Crew Module | In English | |
| CM | Control Monitor | In English | |
| CM | Cargo Manager | In English | |
| CM | Circular Mil | In English | |
| CM | Carmelite Missionaries | In English | → Roman catholic church |
| CM | Congregation of the Mission | In English | → Roman catholic church |
| CMA | Configuration Management Accounting | In English | |
| CMA | Chaperone-mediated autophagy | In English | → Biological sciences |
| CMACS | Central Monitor And Control System | In English | |
| CMAG | Cruise Missile Advanced Guidance | In English | → Military engineering |
| CMAGIC | Color-Magnitude Intercept Calibration | In English | |
| CMAME | Computer Methods in Applied Mechanics and Engineering | In English | → Serial publications, periodicals → Computer science → 531 → Mechanical engineering |
| CMAO | Contract Management Assistance Officer | In English | → 3474 |
| CMAP | Compound Motor Action Potential | In English | |
| CMAR | Configuration Management Action Request | In English | |
| CMAT | Compatible Material | In English | |
| CMB | Configuration Management Board | In English | |
| CMBI | Center for Molecular Biosciences Innsbruck | In English | → Biological sciences |
| CMC | Central Maintenance Computer | In English | → Hardware → Maintenance and logistics |
| CMC | Command Module Computer | In English | |
| CMC | Crew Module Computer | In English | |
| CMC | Chemistry, Manufacturing, and Controls | In English | → Pharmacology, toxicology → Chemical technology |
| CMC | Congregation of The Mother Of Carmel | In English | → Roman catholic church |
| CMCC | Central Mission Control Centre | In English | |
| CMCN | Center of Molecular and Cellular Nanostructure | In English | → Biochemistry, biophysics |
| CMCS | Centralized Maintenance Computer System | In English | → Software → Maintenance and logistics |
| CMDB | Configuration Management Data Base | In English | |
| CMDB | Configuration Management Date Base | In English | → Hardware |
| CMDM | Control Multiplexer/Demultiplexer | In English | |
| CMDS | Configuration Management Data System | In English | |
| CME | Commercial Measuring Equipment | In English | |
| CME | Coronal Mass Ejection | In English | → Astronomy |
| CMEA | Council for Mutual Economic Assistance | In English | → International economic cooperation |
| CMEAS | Consortium for Middle Eastern and African Studies | In English | → Organizations and associations → Language, linguistics, literature → Geography, biography, history |
| CMECAS | Centre for Middle Eastern and Central Asia Studies | In English | → Language, linguistics, literature → Geography, biography, history |
| CMEIS | Centre of Middle Eastern and Islamic Studies | In English | → Islam → Language, linguistics, literature → Geography, biography, history |
| CMENAS | Center for Middle Eastern and North African Studies | In English | → Language, linguistics, literature → Geography, biography, history |
| CMES | Center for Middle Eastern Studies | In English | → Language, linguistics, literature → Geography, biography, history |
| CMF | Claretian Missionary Fathers | In English | → Roman catholic church |
| CMG | Control Moment Gyro | In English | |
| CMHS | Chinese Military History Society | In English | → Organizations and associations → History |
| CMI | Caucasus Media Institute | In English | → Newspapers, journalism |
| CMI | Carmelites of Mary Immaculate | In English | → Christianity |
| CMI | Clay Mathematics Institute | In English | → Mathematics |
| CMIF | Common Module Integration Facility | In English | |
| CMIP | Common Management Information Protocol | In English | → Networks, communication |
| CMIS | Control Monitor Isolation Subsystem | In English | |
| CMIS | Common Module Integration Simulator | In English | |
| CMIS | Computer Management Information System | In English | |
| CMIS | Configuration Management Information System | In English | |
| CML | Commands and Measurement List | In English | |
| CML | Chemical Markup Language | In English | → Programming languages → Chemistry |
| CMM | Coordinate Measurement Machine | In English | |
| CMM | Condition-Monitored Maintenance | In English | → Maintenance and logistics |
| CMM | Centre for Molecular Medicine | In English | → Research institutes → Medicine |
| 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 |
| CMN | Contract Master Network | In English | → 3474 |
| CMO | Class Mix Option | In English | |
| CMO | Configuration Management Office | In English | |
| CMO | Chief Marketing Officer | In English | → 659 |
| CMOS | Complementary Metal Oxide Semiconductor | In English | → Electronics |
| CMP | Configuration Management Plan | In English | |
| CMP | Configuration Management Panel | In English | |
| CmpEn | Composites Engineering | In English | → Serial publications, periodicals → 620 |
| CmpMa | Composites Manufacturing | In English | → Serial publications, periodicals → 620 |
| CMPP | Configuration Management Program Plan | In English | |
| CmpSt | Composite Structures | In English | → Serial publications, periodicals → 620 |
| CMR | Contractor Management Review | In English | → 3474 |
| CMR | Configuration Management Representative | In English | |
| CMR | Common Mode Rejection | In English | |
| CMR | Center Materials Representative | In English | |
| CMR | China Media Research | In English | → Newspapers, journalism |
| CMRB | Contractor Material Review Board | In English | |
| CMRP | Configuration Management Requirements Plan | In English | |
| CMRR | Common Mode Rejection Ratio | In English | |
| CMRS | Configuration Management Requirements Standard | In English | |
| CMS | Code Management System | In English | |
| CMS | Contract Master Schedule | In English | → 3474 |
| CMS | Configuration Management System | In English | |
| CMS | Component Mode Synthesis | In English | |
| CMS | Change Management System | In English | |
| CMS | Conventional Monitoring System | In English | |
| CMS | Center for Migration Studies | In English | → Migrations → Sociology |
| CMS | Centers for Medicare and Medicaid Services | In English | → Medicine |
| CMS | Content Management Server | In English | → Networks, communication → Document processing → Knowledge management |
| CMS | Computational Materials Science | In English | |
| CMS | Concerned Member State | In English | → International relations |
| CMS | Centre for Malaysian Studies | In English | → Language, linguistics, literature → Geography, biography, history |
| CMS | Content Management System = SGC | Système de Gestion de Contenu(s) | In French |
In English | → Document processing → Knowledge management |
| CMSF | Congregation of the Missionaries of Saint Francis Sales | In English | → Roman catholic church |
| CMSI | Command Monitor System Interface | In English | → Human-computer interaction |
| CMSP | Caucasus Media Support Project | In English | → Newspapers, journalism |
| CMSRSC | Maritime Silk Roads Study Centre | In English | → Research institutes → Transport and postal services |
| CMT | Critical Military Target | In English | |
| CMT | Continuum Mechanics and Thermodynamics | In English | → Serial publications, periodicals → 531 → Thermodynamics |
| CMTS | Computerized Maintenance Test System | In English | → Computer science → Maintenance and logistics |
| CMU | Control and Monitor Unit | In English | |
| CMU | Carnegie Mellon University (www.cmu.edu) | In English | → Higher education, universities |
| CMV | Common Mode Voltage | In English | |
| CMVAS | Configuration Management Verification Accounting System | In English | |
| CMW | Compartmented Mode Work Station | In English | |
| 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 |
| CN | Change Notice | In English | |
| CN | Corporate Networks | In English | |
| CNC | Computer Numerical Control | In English | → Computer science |
| CNC | Computer Numerically Controlled | In English | → Computer science |
| CNCBD | China National Center for Biotechnology Development | In English | → Biotechnology |
| CND | China News Digest | In English | → Newspapers, journalism |
| CNDL | Conference of Directors of National Libraries | In English | → Organizations and associations → Libraries |
| CNES | Center for Near Eastern Studies | In English | → Language, linguistics, literature → Geography, biography, history |
| CNG | Compressed Natural Gas | In English | → Chemical technology |
| CNI | Coalition for Networked Information | In English | → Organizations and associations → Libraries |
| 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 |
| CNPL | Center for Nonprofit Leadership | In English | |
| CNPL | Canadian National Poker League | In English | → Organizations and associations → Entertainment |
| CNRL | Communications and Navigation Research Laboratory | In English | → Research institutes → Telecommunications |
| CNS | Catholic News Service (www.catholicnews.com) | In English | → Newspapers, journalism → Roman catholic church |
| CNS | Corporation for National Service (www.cns.gov) | In English | → Public administration, government |
| CNS | Center for Nonproliferation Studies (http://cns.miis.edu) | In English | → Organizations and associations → Polemology → Military engineering |
| CNS | Cognitive Neuroscience Society (www.cogneurosociety.org) | In English | → Organizations and associations → Artificial intelligence → Psychology → Neurology |
| CNS | Computation and Neural Systems (www.cns.caltech.edu) | In English | → Research institutes → Artificial intelligence |
| CNS | Clinical Nurse Specialist | In English | → Medicine |
| CNS | Canadian Northern Shield (www.cns.ca) | In English | → Insurance |
| CNS | Congress of Neurological Surgeons (www.neurosurgeon.org) | In English | → Organizations and associations → Neurology → Surgery, orthopaedics, ophthalmology |
| CNS | Canadian Nuclear Society (www.cns-snc.ca) | In English | → Organizations and associations → Nuclear, atomic, and molecular physics → Nuclear technology |
| CNS | Central Nervous System | In English | → Biological sciences → Anatomy → Neurology |
| CNSA | Contact Network of Spam Authorities | In English | → Telecommunications |
| CNSNS | Communications in Nonlinear Science and Numerical Simulations | In English | → Serial publications, periodicals → Mathematics |
| CNV | Copy Number Variant | In English | → Genetics |
| CNV | Choroidal Neovascularisation | In English | → Pathology → Ophtalmology |
| CNV | Choroidal Neovascularization | In English | → Pathology → Ophtalmology |
| CNWDI | Critical Nuclear Weapons Design Information | In English | → Nuclear technology → Military engineering |
| CO | Contracting Officer | In English | → 3474 |
| CO | Change Order | In English | |
| COA | Center Operations Area | In English | |
| COA | Computational Optimization and Applications | In English | → Serial publications, periodicals |
| COAL | Coal Overseas Association Limited | In English | → Associations |
| CoAlg | Communications in Algebra | In English | → Serial publications, periodicals → Algebra |
| CoArm | Contributions from the Armagh Observatory | In English | → Serial publications, periodicals → Astronomy |
| COAS | Crewman Optical Alignment Sight | In English | |
| CoASP | Comments on Astrophysics and Space Physics | In English | → Serial publications, periodicals → Astronomy → Physics |
| CoAst | Communications in Asteroseismology | In English | → Serial publications, periodicals → Astronomy → Seismology, earthquakes |
| COAST | Competence Network for Advanced Speech Technologies | In English | → Human-computer interaction → Computer-based techniques → Language, linguistics, literature |
| CoAth | Contributions from the Research and Computing Center Academy of Sciences of Athens | In English | → Serial publications, periodicals → Astronomy |
| COB | Communications Office Building | In English | → Telecommunications |
| COB | Chip On Board | In English | → Electronics |
| COB | Children Of Bodom | In English | → Music |
| COB | Church of the Brethren | In English | → Protestant churches |
| COBE | Cosmic Background Explorer | In English | → Astronomy |
| COBOL | Common Business-Oriented Language | In English | → Programming languages |
| CoBos | Contributions from the Bosscha Observervatory | In English | → Serial publications, periodicals → Astronomy |
| 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 |
| CoCam | Contributions from the Cambridge Observatory England | In English | → 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 | |
| CoDAO | Contributions from the Dominion Astrophysical Observatory in Victoria | In English | → Serial publications, periodicals → Astronomy |
| CoDDO | Communications from the David Dunlap Observatory | In English | → Serial publications, periodicals → Astronomy |
| CODEMA | City of Dublin Energy Management Agency | In English | → Energy economics |
| CoDun | Contributions from the Dunsink Observatory Dublin Ireland | In English | → Serial publications, periodicals → Astronomy |