| Abbreviation | Definition |
|---|---|
| ADSA | Advanced Degree Student Association |
| ADSA | Advanced Degree Students Association |
| ADSA | Alberta Debate and Speech Association |
| ADSA | American Dairy Science Association |
| ADSI | Association of Defensive Shooting Instructors |
| ADSO | Association of Democratic Services Officers |
| ADSO | Association of Dental Support Organizations |
| ADST | Association for Diplomatic Studies and Training |
| ADTA | Abbotsford District Teachers Association |
| ADTA | American Dental Therapy Association |
| ADTA | Armed Defense Training Association |
| ADTA | Association of Defense Trial Attorneys |
| ADTA | Atascadero District Teachers Association |
| ADTOI | Association of Domestic Tour Operators of India |
| ADVA | Americal Division Veterans Association |
| ADVB | Association des vignerons broyards |
| ADVR | Association of Directors of Volunteer Resources |
| ADZP | Association of Detergent Zeolite Producers |
| AEA | Actors' Equity Association |
| AEA | Almost Extinguished Association |