| Abbreviation | Definition |
|---|---|
| CHL | Configuration History Log |
| CHM | Compiled HTML file |
| CHN | Ethnograph 3 Data |
| CHP | Ventura Publisher Chapter file |
| CHR | Borland Language Stroke Character Font file |
| CHR | Character set (Turbo C - Turbo Pascal) |
| CHT | Chart file ( Harvard Graphics 2.0, SoftCraft Presenter) |
| CHT | dBASE Interface file for ChartMaster |
| CHZ | Compressed file archive (CHARC) |
| CIF | Caltech Intermediate Format graphics file |
| CIF | CD (Compact Disk) Image File |
| CIF | IUCr Crystallographic Information File |
| CIF | Ventura Publisher Chapter Information File |
| CIL | Clip gallery download package (Art Gallery) |
| CIM | SimCity 2000 Game data |
| CIM | Ultimate Draw C Text Mode Image File |
| CIN | INI file change control file (OS/2) |
| CIX | Database index (Turbo C Utilities) |
| CK1 | Game data (iD/Apogee Commander Keen 1) |
| CK2 | Game data (iD/Apogee Commander Keen 2) |