| Abbreviation | Definition |
|---|---|
| ASSD | Associate of Science in Software Development |
| ASTD | American Society of Traininig Development |
| ASTID | Astrobiology Science and Technology Instrument Development |
| ASUC | All Sections Under Construction |
| ASUD | Achieving Sustainable Urban Development |
| ATD | Association for Talent Development |
| ATD | Association of Talent Development |
| ATDC | Advanced Technology Development Center |
| ATDC | Advanced Technology Development Complex |
| ATDC | Anniversary Training and Development Conference |
| ATDD | Acceptance Test Driven Development |
| ATDD | Acceptance Test–Driven Development |
| ATDD | Acquisition Training And Development Directory |
| ATDF | Advanced Technology Development Facility |
| ATDF | African Technology Development Forum |
| ATDF | Agricultural Technological Development Foundation |
| ATDF | Armenia Territorial Development Fund |
| ATDF | Armenian Territorial Development Fund |
| ATDM | Advanced Technology Development and Mitigation |
| ATDP | Academic Talent Development Program |