| ACEX | Arctic Coring Expedition |
| ACH | Automated Clearing House |
| AESTO | Advanced Earth Science and Technology Organization (Japan) |
| AGI | American Geophysical Institute |
| AGU | American Geophysical Union |
| AMS | American Meteorological Society |
| AOGS | Asia-Oceana Geosciences Society |
| APC | Advanced Piston Core |
| APCT | APC Temperature Tool |
| API | American Petroleum Institute |
| APL | Ancillary Project Letter |
| APP | Annual Program Plan |
| Argo | Global profiling float project |
| ASLO | American Society for Limnology and Oceanography |
| AUV | Autonomous Underwater Vehicle |
| BATS | Bermuda Atlantic Time-series Study |
| BCR | Bremen Core Repository |
| BGS | British Geological Survey |
| BHA | Bottom Hole Assembly |
| BoG | Board of Governors |
| BP | Before Present |
| BSR | Bottom Simulator Reflector |
| CalCOFI | California Cooperative Oceanic Fisheries Investigations |
| Caro-COOPS | Carolinas Coastal Ocean Observing and
Prediction System |
| CB-RMM | Core barrel - retrievable memory module |
| CBOS | Chesapeake Bay Observing System |
| CCD | Carbonate Compensation Depth |
| CDEX | Center for Deep Earth Exploration |
| CDP | Complex Drilling Projects |
| CI | Cyberinfrastructure |
| CLEANER | Collaborative Large-scale
Engineering Analysis Network for Environmental Research |
| CLIVAR | CLImate VARiability and Predictability |
| CMCR | Center for Advanced Marine Core Research (Kochi University) |
| CMO | Central Management Office |
| CNRS | Centre National de la Research Scientific (France) |
| CO | Contracts Officer |
| COI | Conflict of Interest |
| CoML | Census of Marine Life |
| COMPS | Coastal Ocean Monitoring and Prediction
System (Univ. of South Florida) |
| CoOP | Coastal Ocean Processes |
| CORE | Consortium for Oceanographic Research and
Education |
| CORK | Circulation Obviation Retrofit Kit |
| CORMP | Coastal Ocean Research and Monitoring Project |
| COSEE | Cooperative Ocean Science Excellence in Education |
| COTS | Commercial Off The Shelf |
| CUSP | Conference on U.S. Participation in IODP |
| DEOS | Dynamics of Earth and Ocean Systems |
| DIS | ICDP Drilling Information System |
| DLESE | Digital Library for Earth System Education |
| DMAC | Data Management and Communications |
