| Abbreviation | Definition |
|---|---|
| AQ | Antarctica |
| AQAP | al Quaeda in the Arabian Peninsula |
| AR | Argentina |
| ARAI | Archives and Records Association, Ireland |
| ARE | Arab Republic of Egypt |
| ARYM | Antigua República Yugoslava de Macedonia |
| ASSRT | Autonomous Soviet Socialist Republic Of Turkistan |
| AT | Austria |
| ATA | Antarctica |
| AU | Australia |
| AUSCANNZUKUS | Australia, Canada, New Zealand, United Kingdom, United States |
| AUT | Austria |
| AVRDC | Asian Vegetable Research and Development Center |
| AZ | Azerbaijan |
| B | Belgium |
| B&H | Bosnia And Herzegovina |
| B5C | Big 5 Countries |
| BA | Bosnia-Herzegovina |
| BA | Buenos Aires, Argentina |
| BAF | British And French |