| Acronym | Meaning |
| CREG | Cross-reactive Group |
| CREME | Cosmic Ray Effects On Micro-Electronics |
| CREMSEE | Cyclotron Resonance From Microwave-induced Secondary Electron Emissions |
| CREST | Center For Renewable Energy And Sustainable Technology |
| CRF | Chromatographic Response Function |
| CRF | Chronic Renal Failure |
| CRF | Corticotropin-releasing Factor |
| CRGT | Chemically Recuperated Gas Turbine |
| CRH | Corticotropin-releasing Hormone |
| CRHF | Complex-restricted Hartree-Fock |
| CRIB | Computerized Resources Information Bank |
| CRIMS | Chemical Reaction Interface Mass Spectrometry |
| CRINEPT | Cross-correlated Relaxation-enhanced Polarization Transfer |
| CRIOSA | Classical Reactive Infinite Order Sudden Approxn. |
| CRIP | Cysteine-rich Intestinal Protein |
| CRIS | Cosmic-Ray Isotope Spectrometer |
| CRISM | Compact Reconnaissance Imaging Spectrometer For Mars |
| CRISTA | Cryogenic Infrared Spectrometers And Telescopes For The Atmosphere |
| CRL | Central Regional Laboratory |
| CRL | Certified Reporting Limit |
| CRLAS | Cavity Ringdown Laser Absorption Spectroscopy |
| CRM | Certified Reference Material |
| CRM | Chemical Remanent Magnetization |
| CRM | Continuous Radon Monitor |
| CRMGT | Channel Regulated MOS-gated Thyristor |
| CRMMA | Chemical Reference Material Manufacturers Association |
| CROCUS | Cost Of The Energy Service Related To Overall Efficiency With Incentives For Infrastructure At Unchanged Service |
| CROSSBOW | Computerized Retrieval Of Organic Structures Based On Wiswesser |
| CROW | Contained Recovery Of Oily Wastes |
| CROWN | Combines Rotation With Nutation |
| CRP | C-reactive Protein |
| CRP | CAMP Receptor Protein |
| CRP | Carbon Fiber Reinforced Plastics |
| CRQL | Contract Required Quantitation Limit |
| CRR | Carbon Removal Rate |
| CRREL | US Army Cold Regions Research And Engineering Laboratory |
| CRRES | Combined Release And Radiation Effects Satellite |
| CRS | Controlled Release Society |
| CRS | Coordinate-representation Sudden (decoupling Method For Mol. Inelastic Collisions) |
| CRSS | Critical Resolved Shear Stress |
| CRT | Continuously Regeneration Trap |
| CRT | Cathode Ray Tube |
| CRTA | Controlled Rate Thermal Analysis |
| CRTF | Centralized Recovery And Treatment Facility |
| CRU | Constitutional Repeating Unit |
| CRWQCB | California Regional Water Quality Control Board |
| CRYSIS | Cryogenic Stockholm Ion Source |
| CS | Compton Scattering |
| CS | Centrifugal Sudden (approximation) |
| CS | Chemical Shift |