| Abbreviation | Definition |
|---|---|
| CLPA | Clinical Laboratory Professionals Association |
| CLS | Canada Land Surveyor |
| CLSA | California Land Surveyors Association |
| CLSIG | Commercial, Legal and Scientific Information Group (CILIP) |
| CLTA | Califomia Land Title Association |
| CLTA | California Language Teachers Association |
| CLTA | Corporate Law Teachers Association |
| CLUE | Comprehensive Loss Underwriters Exchange |
| CLUG | Canberra Linux Users Group |
| CLUG | Canterbury Linux Users Group |
| CLUG | Cape Linux Users Group |
| CLUG | CERN Linux Users Group |
| CLUG | Clark Linux Users Group |
| CLUG | Cleveland Linux Users Group |
| CLUG | Corunna Linux User Group |
| CLUG | Cracow Linux User Group |
| CMA | Cabinet Makers' Association |
| CMA | Canadian Medical Association |
| CMA | Chemical Manufacturers Association |
| CMA | Columbus Medical Association |