| csi | CARE-S InfoWorks Water Quality Data |
| csj | BlackBerry Code Signing Data |
| csk | BlackBerry Code Signing Keys |
| csk | Copernic 2001 Skin Data |
| cskin | CD Art Display Skin |
| csl | CorelDraw Symbol Library |
| csm | Chemical Style Markup Language Data |
| csm | Mail.dat Container Summary File |
| csml | Chemical Style Markup Language Data |
| csmo | Free College Schedule Maker Data |
| csn | CopyMate Raw Points Cloud Scan Data |
| csn | Race Studio 2 Custom Sensors Data |
| csom | Qualcomm Eudora for Mac Creator Code Data |
| cson | CoffeeScript Object Notation |
| csp | CHARTrunner Pareto Style |
| cspl | Mozilla Firefox CSPL Data |
| csplan | SPSS Sampling Plan |
| csr | Certificate Signing Request Data |
| css | Scream Center for Seismic Studies Data |
| css1 | CSS Backup |
| cssr | CSD Crystal Structure Search and Retrieval Data |
| csstore | iOS Cache Data |
| cssx | Now Platform External CSS |
| cst | ACDSee Canvas Custom Set |
| cst | CHARTrunner Control Chart Style |
| cst | ClearSilver Template File |
| cst | Medbasin Model Calibration Data |
| cst | SAM Constraints Data |
| cst | SWAT Weather Forecast Input Data |
| csup | Clan Short Roster Database |
