Encyclopedias, Almanacs, Transcripts, and Maps
- Atum
- auditory canal
- Audubon, John James (1785 – 1851) American Naturalist, Artist, and Ornithologist
- Augustine of Canterbury
- Augustine of Hippo
- Auks, Puffins, and Murres (Alcidae)
- Aulopiformes (Lizardfishes and Relatives)
- Aum Shinrikyō
- Australia Day
- Australian Chats (Epthianuridae)
- Australian Creepers (Climacteridae)
- Australian Fairy-Wrens (Maluridae)
- Australian Ground Frogs (Limnodynastidae)
- Australian Honeyeaters (Meliphagidae)
- Australian Indigenous Religions
- Australian Indigenous Religions: Aboriginal Christianity
- Australian Indigenous Religions: An Overview
- Australian Indigenous Religions: New Religious Movements
- Australian Prime Ministers
- Australian Robins (Petroicidae)