Encyclopedias, Almanacs, Transcripts, and Maps
- Authari
- authentic modes
- autograft
- automatic direction finder
- automatic frequency control
- automatic tuning control
- autonomous underwater vehicle
- autumn crocus
- Aux Cayes
- Auyuittuq National Park
- Ava (village, Myanmar)
- Avacha
- Avalos, Ferdinando Francesco d'
- Avarua
- Avdira
- Avebury, John Lubbock, 1st Baron
- Aveiro
- Avellaneda, Nicolás
- Avenches
- Aventine