| Acronym | Meaning |
| CGTF | Cartesian Gaussian-type Function |
| CGTO | Cartesian Gaussian-type Orbital |
| CGTO | Combination Of Gaussian Type Orbitals |
| CGTO | Contracted Gaussian-type Orbital |
| CH-CI | Core Hole Configuration Interaction |
| CHA | Concept Hazard Analysis |
| CHA | Chemical Hamiltonian Approach |
| CHA | Concentric Hemispherical Analyzer |
| CHAART | Center For Health Applications Of Aerospace-Related Technologies |
| CHAMP | Community Health Air Monitoring Program |
| CHAMPP | Computer Hardware |
| CHAOS | Canadian High Acceptance Orbit Spectrometer |
| CHAP | Chronic Hazard Advisory Panel |
| CHAPEL | Continuous Hydrogen Analysis By Pressure Evaluation In Liquids |
| CHARM | Complex Hazardous Air Release Model |
| CHARM | Coupled Hydrosphere-Atmosphere Research Model |
| CHARMM | Chemistry At HARvard Macromolecular Mechanics |
| CHC | Chlorinated Hydrocarbon |
| CHCS | Chemical Hazards Communication Society |
| CHD | Coronary Heart Disease |
| CHDF | Capillary Hydrodynamic Fractionation |
| CHEC | Commonwealth Human Ecology Council |
| CHEF | Chelation Enhanced Fluorescence |
| CHEF | Contour-clamped Homogeneous Field Electrophoresis |
| CHELEQ | Charge Electronegativity Equalization |
| CHELP | CHarges From ELectrostatic Potential |
| CHELPG | CHarges From ELectrostatic Potential |
| CHEM | Chemical Collection Database (accessible Through OLS) |
| CHEMATA | Chem. Mechanism Adaptation To Tropospheric Applications |
| CHEMFET | Chem. Modified Field Effect Transistor |
| CHEMICS | Combined Handling Of Elucidation Methods For Interpretable Chemical Structures |
| CHEMRAWN | Chemical Research Applied To World Needs |
| CHEMTREC | Chemical Transportation Emergency Center |
| CHEQ | Chelation Enhanced Quenching |
| CHERS | Charge Exchange Recombination Spectroscopy |
| CHES | 3-(cyclohexylamino)ethylsulfonic Acid |
| CHESS | Community Health And Environmental Surveillance System |
| CHESS | Cornell High-Energy Synchrotron Source |
| CHESS | Council For Health And Environmental Safety Of Soils |
| CHEST | Combined Higher Education Software Team |
| CHF | Coulomb Hartree-Fock |
| CHF | Congestive Heart Failure |
| CHF | Coupled Hartree-Fock |
| CHF | Critical Heat Flux |
| CHF-PT-EB | Coupled Hartree-Fock-perturbation Theory-extended Basis |
| CHFEP | Coreless Hartree-Fock Effective Potential |
| CHFET | Complementary Heterojunction Field-effect Transistor |
| CHFPT | Coupled Hartree-Fock Perturbation Theory |
| CHI | Coaxial Helicity Injection |
| CHICO | Compact Heavy-ion Counter |