| Abbreviation | Definition |
|---|---|
| CPT | Cone Penetration Test |
| CPT | Cone Potentiometer Test |
| CPTU | Piezocone Penetration Test |
| CPZ | Coastal Polynya Zone |
| CR | Columbia River |
| CRA | Country, Region, and Area |
| CRISP | Centre for Remote Imaging, Sensing, and Processing |
| CRN | Cosmogenic Radionuclide |
| CRT | Cedar River Trail |
| CRUD | Chalk River Unidentified Deposits |
| CSAV | Center for Study of Active Volcanoes |
| CSM | Certified Survey Map |
| CSR | Chase Ranch, California, Seismograph station |
| CSRA | Central Savannah River Area |
| CSRS | Canadian Spatial Reference System |
| CSTSC | Canadian Soil Thin Section Collection |
| CSVH | Catalog of Submarine Volcanoes and Hydrological phenomena |
| CSVZ | Central Southern Volcanic Zone |
| CSZ | Contract Strain Zone |
| CT | Consolidated Test |