| Abbreviation | Definition |
|---|---|
| CWSU | Caution and Warning Status Unit |
| CWSU | Condensate Water Servicing Unit |
| CX | Chemical X |
| CX | Color Exterior film |
| CXOLEV | ConeXpress Orbital Life Extension Vehicle |
| CY | CYcle |
| CYL | Cylinder |
| D | Deck |
| D | Delivery |
| D | Delta |
| D | Down |
| D | Drag |
| D&C | Display and Control |
| D&CS | Display and Control Sub-system |
| D&O | Description and Operations |
| D&P | Drain and Purge |
| D&PD | Definition and Preliminary Design |
| D&PS | Design and Performance Specification |
| D&R | Definition and Requirement |
| D/A | Digital-to-Analog |