| Abbreviation | Definition |
|---|---|
| CEOP | Coordinated Enhanced Observing Period |
| CEOS | Committee on Earth Observation Satellites |
| CEP | Caribbean Environment Program |
| CEP | Committee on Environmental Protection |
| CEPEX | Central Equatorial Pacific Experiment |
| CEPEX | Controlled Ecosystems Pollution Experiment |
| CEPIS | Pan American Centre for Sanitary Engineering and Environmental Sciences |
| CEPT | Conférence Européenne des Postes et des Télécommunications |
| CEPT | European Conference of Postal and Telecommunications Administrations |
| CEQ | Council on Environmental Quality |
| CER | Coordinated Ecosystem Research |
| CERCLA | Comprehensive Environmental Response Compensation and Liability Act |
| CERI | Center for Environmental Research Information |
| CERN | European Organization for Nuclear Research |
| CESAR | Canadian Expedition to Study the Alpha Ridge |
| CEST | Coastal Environmental Science and Technology |
| CETA | Cetacean Education Through Awareness |
| CFC | Combined Federal Campaign |
| CFDA | Catalog of Federal Domestic Assistance |
| CFM | ChloroFluoroMethane |