ADA
- ADA (buffer)
- ADA collider
- Ada (disambiguation)
- Ada (programming language)
- Adana Şakirpaşa Airport
- Adaptive Design Association
- Adenosine deaminase
- Advanced Distribution Automation
- Aerolínea de Antioquia
- Aeronautical Development Agency
- After the Development of Agriculture
- Air Defense Artillery Branch
- Airline Deregulation Act
- Alternative Distribution Alliance
- Amazon Development Agency
- American Decency Association
- American Dental Association
- American Diabetes Association
- American Dietetic Association
- Americans for Democratic Action
- Americans with Disabilities Act of 1990
- Amigos dos Amigos
- Analog-to-digital converter
- Angehöriger der Armee
- Antideficiency Act
- Apple Design Awards
- Armée de l'Air
- Asociación Deportiva Agropecuaria
- Assistant district attorney
- Association of Drainage Authorities
- Australian Dental Association
- Australian Digital Alliance
- Austrian Development Agency
- Azodicarbonamide
- Cardano (blockchain platform)
- Dangme language
- ISO 639-2
- ISO 639-3