| Abbreviation | Definition |
|---|---|
| ACWI | All Country World Index |
| ADFO | Alternate Downstream Flow Options |
| ADIR | Adirondacks |
| AE | Alkaline Earth |
| AEDD | Arctic Environmental Data Directory |
| AEE | Australian European Expedition |
| AF | Across Flats |
| AF | Anti-Fall |
| AFR | Average Flow Rate |
| AFTA | Apatite Fission Track Analysis |
| AGO | Automated Geophysical Observatory |
| A-GPS | Assisted Global Positioning System |
| AGSG | Asian Geography Specialty Group |
| AGU | American Geophysical Union |
| AGWA | Automated Geospatial Watershed Assessment |
| AHD | Australian Height Datum |
| AIH | Area Including Holes |
| ALS | Airborne Laser Survey |
| ALSF | Aggregates Levy Sustainability Fund |
| AMAP | Arctic Monitoring and Assessment Program |