| ccad | Claris CAD Data |
| ccc | Microsoft Comic Chat Conversation Data |
| ccd | SmartWare Compiled Cartridge Descriptor |
| cce | Cumulus 6 Category Export Data |
| ccf | Cryptload Container Format File |
| cch | .NET Security Cache |
| ccj | Compiled Crossword Applet |
| ccj | Corticon Server Rulesets Data |
| cck | COMcheck Data |
| ccl | CFX CCL File |
| ccm | Multimedia Fusion Custom Menu Data |
| ccm | Lotus CC:Mail |
| ccmg | STAR-CD v4 Solver Ready Geometry Data |
| ccmp | STAR-CD v4 Results Data |
| ccmt | STAR-CD v4 Transient Data |
| ccp4 | Collaborative Computational Project Number 4 Format Data |
| ccr | ASTM Continuity of Care Record |
| ccrf | Saba Centra Recording Studio Recording |
| ccrz | Saba Centra Recording Studio Recording |
| ccu | CryptLoad Update Data |
| ccv | SAP Business Objects Crystal Vision Report |
| ccw | Crossword Compiler Crossword File |
| ccwsln | Connected Components Workbench Data |
| ccz | Client-Course Manager Customized Report Distribution Data |
| cd | STK City Database Main File |
| cdb | Sybase PowerDesigner Conceptual Data Model Backup |
| cdbcmsg | CIM Database CMSG Data |
| cdcom | Circuit Diagram Compiled Components File |
| cde | CADKEY Dynamic Extension |
| cded | Canadian Digital Elevation Data |
| cdf | Microsoft Channel Definition Format Data |
| cdf | ANDI/netCDF Chromatography Data |
| cdf | Affymetrix Chip Description File |
| cdf | netCDF Data |
| cdf | ECMG Content Definition File |