| Abbreviation | Definition |
|---|---|
| CREW | Committed Republicans Energized To Win |
| CRI | Compatible Reformulated Input |
| CRI | Congressional Record Index |
| CRIX | Clinical Research Information Exchange (FDA and NCI) |
| CRM | Customer Relationship Management |
| CRO | Contract Regulatory Organization |
| CROBA | Consular Report Of Birth Abroad |
| CROSS | Customs Rulings Online Search System |
| CRPL | Central Radio Propagation Laboratory |
| CRS | Campaign Reporting System |
| CRS | Community Relations Service |
| CRS | Congressional Record Service |
| CRST | Cheyenne River Sioux Tribe |
| CRT | Campaign Research Team |
| CRT | case report tabulations |
| CS | Civil Servant |
| CS | Confederate States |
| CSA | Commuter Student Association |
| CSA | Confederate States Archiver |
| CSA | Confederate States of America |