| Abbreviation | Definition |
|---|---|
| CID | Compare and Ignore Data |
| CIR | Clear Instant Reset |
| CIR | Configuration In Run |
| CK | Character Kill |
| CK | Chip Kill |
| CL | Command Language |
| CLA | Constant Linear Address |
| CLC | Clear Carry Flag |
| CLD | Clear Direction Flag |
| CLF | Clear Flags |
| CLI | Clear Interrupt-Enable Flag |
| CLIM | Command Line Interface Manager |
| CLK | Clock |
| CLN | Clean |
| CLOB | Character Large Object Block |
| CLR | Clear |
| CLS | Clear Last Screen |
| CLTS | Clear Task Switched Flag |
| CLW | Character, Line, and Word |
| CMC | Complement Carry Flag |