| Abkürzung | Bereich | Staat | Bedeutung |
| CHKDSK | Software | Check Disk | |
| CHMOD | Computer | Change Mode | |
| CIM | Computer | Computer Integrated Manufacturing (Computerunterstützte Produktion) | |
| CIP | Computer | Computer Integrated Processing (CIM für die verfahrenstechnische Industrie) | |
| CISC | Computer | Complex Instruction Set Computing | |
| CKSM | Computer | D | Checksumme |
| CLS | Software | Clear Screen | |
| cm | Einheit | Zentimeter | |
| CMMU | Computer | Cache / Memory Management Unit | |
| CMY | Farbe | Cyan-Magenta-Yellow (Grundfarben) | |
| CMYK | Farbe | Cyan-Magenta-Yellow Black (Grundfarben) | |
| CNA | Person | Certified Netware Administrator | |
| CNC | Technik | Computer Numerical Control | |
| CNE | Person | Certified Netware Engineer | |
| CNI | Person | Certified Netware Instructor | |
| CNN | Gesellschaft | USA | Cable News Network |
| COBOL | Computer | Common Business Oriented Language (Programmiersprache) | |
| COM | Software | Common Objekt Model | |
| cos | Mathematik | Cosinus | |
| cot | Mathematik | Cotangens | |
| CP | Technik | Copy Protected | |
| Software | Copy | ||
| CP/M | Software | Control Program for Microcomputers (Betriebssystem) | |
| CPE | Technik | Central Processing Element | |
| CPI | Computer | Common Programming Interface | |
| Characters per Inch | |||
| CPIC | Computer | Common Programming Interface for Communication | |
| CPP | Software | C Plus Plus | |
| CPS | Computer | Characters per Second | |
| Cycles per Second | |||
| CPU | Computer | Central Processing Unit | |
| CR | Software | Carriage Return | |
| CROM | Computer | Control Read Only Memory | |
| CS | Computer | Chip Select | |
| Software | Clear to Send | ||
| Code Segment | |||
| CSU | Computer | Channel Service Unit | |
| CSV | Software | Comma-Separated Variables | |
| CTPA | Technik | Coax-to-Twisted-Pair Adapter | |
| CTRL | Computer | Control | |
| CTS | Technik | Clear to Send | |
| CUB | Computer | Cursor Backward | |
| CUD | Computer | Cursor Down | |
| CUF | Computer | Cursor Forward | |
| CUI | Computer | Common User Interface | |
| CUP | Computer | Cursor Position | |
| CUU | Computer | Cursor Up | |
| CVGA | Computer | Color Video Gaphics Array | |
| CWD | Software | Convert Word to Double Word | |
| CYMK | Farbe | Cyan-Yellow-Magenta-Black (Grundfarben) |