| CACSA | Publius Servilius Casca Longus / Canadian Astronomical Society |
| CAD | Computer-Aided Design |
| CAMH | Centre For Addiction And Mental Health |
| CARP | Covid-19 Advanced Respiratory Physiology / Common Address Redundancy Protocol |
| CART | Council Aviation Recovery Taskforce / Common Admission Retail Test |
| CASA | Current Account Savings Accounts |
| CASB | Cloud Access Security Broker |
| CATHOLIC | Roman Catholic |
| CBA | Consumer Bankers Association / Collective Bargaining Agreement |
| CBE | Competency-Based Education |
| CBT | Computer Based Test |
| CCCO | Central Committee For Conscientious Objectors |
| CCNA | Cisco Certified Network Associate |
| CCPC | Centralised Clearing Processing Centre / Competition And Consumer Protection Commission |
| CCPM | Critical Chain Project Management |
| CCU | Critical Care Unit |
| CD | Compact Disc / Certificate Of Deposit |
| CDI | Capacitor Discharge Ignition |
| CDL | Commercial Driver'S License |
| CDM | Cash Deposit Machine |
| CDMO | Contract Development And Manufacturing Company |
| CDN | Content Delivery Network |
| CDP | Child Development And Pedagogy |
| CDR | Call Detail Record |
| CDW | Collision Damage Waiver |
| CEOP | Cyclophosphamide-Epirubicin-Oncovin-Prednisone |
| CERA | Consortium For E-Resources In Agriculture / Cambridge Energy Research Associates |
| CF | Confer/Conferatur |
| CFM | Cubic Feet Per Minute |
| CFP | Certified Financial Planner |
| CGEY | Computer-Generated Imagery / Cap Gemini Ernst And Young |
| CGM | Continuous Glucose Monitoring |
| CH2CL2 | Dichloromethane |
| CHD | Congenital Heart Defects |
| CHERISH | To Care For Tenderly; Nurture |
| CHF | Congestive Heart Failure / Swiss Franc |
| CHIP | Children'S Health Insurance Program |
| CI | Circle Inspector |
| CIAM | Customer Identity And Access Management |
| CIBC | Canadian Imperial Bank Of Commerce |
| CIF | Customer Information File |
| CIO | Chief Information Officer |
| CIPD | Chartered Institute Of Personnel And Development |
| CISA | Certified Information Systems Auditor / Cybersecurity And Infrastructure Security Agency |
| CISO | Chief Information Security Officer |
| CIT | Computers And Information Technology |
| CLABSI | Central Line-Associated Bloodstream Infection |
| CLE | Continuing Legal Education |
| CLI | Command-Line Interface |
| CLM | Contract Lifecycle Management |
| CMA | Certified Management Accountant |
| CMDB | Configuration Management Database |
| CME | Continuing Medical Education |
| CMI | Cell-Mediated Immunity |
| CMMS | Computerized Maintenance Management System |
| CMO | Chief Medical Officer / Chief Marketing Officer |
| CMS | Content Management System |
| CMV | Cytomegalovirus |
| CNA | Certified Nurse Aide / Certified Nursing Assistants |
| COBOL | Common Business-Oriented Language |
| CODA | Child Of Deaf Adult |
| COI | Certificate Of Incorporation / Certificate Of Insurance |
| COLD-BLOODED | Done Or Acting Without Consideration, Compunction, Or Clemency |
| COMMUNITY | |
| COMPOSITE | |
| COMPUTING | Common Operating Machine Purposely Used For Technological And Educational Research |
| CONCUR | |
| CONFIDE | |
| CONSOLIDATE | To Combine Into One Body |
| COPD | Chronic Obstructive Pulmonary Disease |
| COR | Certificate Of Recognition / Coronary Observation Radio |
| COV | Coronavirus |
| CPC | Code Of Civil Procedure / Central Pay Commission |
| CPE | Customer Premises Equipment |
| CPG | Consumer Packaged Goods |
| CPI | Consumer Price Index |
| CPIM | Communist Party Of India (Marxist) / Critical Path Innovation Meetings |
| CPOH | Central Periodical Overhauling Workshop / Clinical Projects In One Health |
| CPP | Card Protection Plan |
| CPQ | Configure, Price, Quote |
| CPR | Cardiopulmonary Resuscitation |
| CRED | Collaborating Centre For Research On The Epidemiology Of Disasters |
| CREDENTIALS | |
| CREDIBLE | Capable Of Being Believed |
| CRM | Customer Relationship Management |
| CRT | Cathode-Ray Tube |
| CRV | Comfortable Runabout Vehicle / Compact Recreation Vehicle |
| CSPM | Cloud Security Posture Management |
| CSR | Corporate Social Responsibility |
| CST | Central Sales Tax |
| CSU | Channel Service Unit |
| CTE | Chronic Traumatic Encephalopathy |
| CTO | Chief Technology Office |
| CTP | Computer-To-Plate / Communications Timing Procedure |
| CTS | Cheque Truncation System |
| CUSTOM | Center For Uncertain Systems Tools For Optimization And Management |
| CUV | Compact Utility Vehicle / Crossover Vehicle |
| CVA | Cerebral Vascular Accident |
| CVO | Chief Vigilance Officer |
| CX | Customer Experience |
| CYN | Certificate In Yoga And Naturopathy / Create Your Network |