| Abbreviation | Definition |
|---|---|
| CISAA | Conference of Independent Schools Athletics Association |
| CISC | Canadian Indonesian Social Club |
| CISC | Criminal Intelligence Service Canada |
| CISC | Criminal Intelligence Service of Canada |
| CISD | Canadian Industrial Security Directorate |
| CISG | Canadian Instrumentation Services Group |
| CISOntario | Conference of Independent Schools of Ontario |
| CISS | Canadian International School System |
| CISS | Canadian International Student Services |
| CISS | Canadian Internetworked Scientific Supercomputer |
| CISS | Canadian ISBN Service System |
| CISSA | Canadian Immigrant Settlement Sector Alliance |
| CISSN | Canadian Information Security Support Network |
| CISSS | Centre Intégré de Santé et de Services Sociaux des Laurentides |
| CIT | Canadian Income Tax |
| CIT | Canadian International Trading |
| CITA | Canadian Imaging Trade Association |
| CITA | Canadian Independent Telecommunications Association |
| CITA | Canadian Industrial Transportation Association |
| CITA | Canadian Institute for Theoretical Astrophysics |