ADHS
- 2-amino-3,7-dideoxy-D-threo-hept-6-ulosonate synthase
- Acton District High School
- Alfred Deakin High School
- Almonte and District High School
- Appalachian Development Highway System
- Arizona Department of Health Services
- Arnprior District High School
- Athens District High School
- Athens Drive High School
- Attention-deficit hyperactivity disorder