| Abbreviation | Definition |
|---|---|
| 10T | 1 0 Tea |
| A | AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAC$FHFGRGF%RGRHGGRFV |
| A | Acceleration |
| A | Aft |
| A | Alpha |
| A | Ampere |
| A | Analog signal |
| A | Angstrom |
| A&A | Advertise and Award |
| A&E | Architects and Engineering |
| A&E | Architectural and Engineering |
| A&I | Assembly and Installation |
| A&L | Approach and Landing |
| A&P | Attitude and Pointing |
| A&PS | Administration and Program Support (MSFC Directorate) |
| A&R | Automation and Robotics |
| A&RC | Application and Resource Control |
| A&TA | Assembly and Test Area |
| A&V | Assembly and Verification |
| A/A | Air to Air |