| Abbreviation | Definition |
|---|---|
| CRAQ | Centre for Research in Astrophysics of Qu??bec |
| CRAQ | Centre for Research in Astrophysics of Québec |
| CRBT | Cosmic Ray Background Test |
| CRcosmicrays | Cosmic Rays are high energy radiation originating outside the solar system. |
| CREAM | Cosmic Ray Energetics And Mass |
| CRL | Compound Refractive Lens |
| CRS | Cambridge Reference Sequence |
| CRSF | Cyclotron Resonant Scattering Feature (various locations) |
| CRSR | Center for Radiophysics and Space Research |
| CRTS | Catalina Real-Time Transient Survey |
| CRTS | Centre Royal de Teledetection Spatiale |
| CSAS | Colorado Springs Astronomical Society |
| CSF | Clustered Star Formation |
| CSFH | Cosmic Star Formation History |
| CSFT | Continuous Space Fourier Transform |
| CSM | Central Star Magnitude |
| CSM | circum-stellar material |
| CSMA | Committee on the Status of Minorities in Astronomy |
| CSPAR | Center for Space Plasma and Aeronomic Research |
| CSWA | Committee on the Status of Women in Astronomy |