| Acronym | Meaning |
| CEN | Comite Europeen De Normalization |
| CENP | Centromere-associated Protein |
| CENSA | Collaborative Electronic Notebook Systems Association |
| CEOOWG | Commercial Earth And Ocean Observations Working Group |
| CEPA | Canadian Environmental Protection Act |
| CEPA | Correlated Electron Pair Approxn. |
| CEPA | Coupled Electron Pair Approximation |
| CEPA-2V | Coupled-electron-pair Approxn. (with) Variational (method) |
| CEPA-SD | Coupled-electron-pair Approxn. (with) Single (and) Double Excitations |
| CEPA-VAR | Coupled-electron-pair Approxn.-variational |
| CEPEX | Central Equatorial Pacific Experiment |
| CEPEX | Controlled Ecosystem Pollution Experiment |
| CEPH | Centre D'Etudes Du Polymorphisme Humain |
| CEPM | Coupled Electron Pair Method |
| CEPOD | Catalyzed Electrochemical Plutonium Oxide Dissolution |
| CEPP | Chemical Emergency Preparedness Plan |
| CEPPO | Chemical Emergency Preparedness And Prevention Office |
| CEPS | Chemically Enhanced Primary Sedimentation |
| CEPT | Cholesterol Ester Transfer Protein |
| CEQ | Council On Environmental Quality |
| CEQ | Collinear Exact Quantum (method In Reactive-scattering Calcn.) |
| CEQA | California Environmental Quality Act |
| CEQB | Collinear Exact Quantum (with Adiabatic) Bending (energy) (method For Reactive Scattering) |
| CERCLA | Comprehensive Environmental Response |
| CERCLIS | Comprehensive Environmental Response |
| CERDA | Coincident Elastic Recoil Detection Analysis |
| CERDIP | Ceramic Dual-inline Package |
| CERES | Cloud And The Earth's Radiant Energy System |
| CERES | Coalition For Economically Responsible Economies |
| CERES | Crop Estimation Through Resource And Environment Synthesis Model |
| CERI | Center For Environmental Research Information |
| CERL | Construction Engineering Research Laboratory (US Army) |
| CERL | Corvallis Environmental Research Laboratory |
| CERN | Conseil Europeen Pour La Recherche Nucleaire |
| CERPIES | Collision Energy Resolved Penning Ionization Electron Spectra |
| CERT | Const. Extension Rate Tensile |
| CES | Committee On Earth Science (Office Science & Technology Policy) |
| CESAR | Canadian Expedition To Study The Alpha Ridge |
| CESAR | Chemically Enhanced Solubilization For Aquifer Remediation |
| CESARS | Chemical Evaluation Search And Retrieval System |
| CESE | Complex Eigenvalue Shroedinger Equation |
| CESQG | Conditionally Exempt Small Quantity Generator |
| CESR | Cornell Electron Storage Ring |
| CESR | Conduction Electron Spin Resonance |
| CET | Center For Environmental Technology |
| CET | Collisional Energy Transfer |
| CETA | Carbon Emission Trajectory Assessment Model |
| CETO | Cartesian Exponential Type Orbital |
| CETP | Channel Equiv. Of A Theor. Plate |
| CETP | Cholesteryl Ester Transfer Protein |