Encyclopedias, Almanacs, Transcripts, and Maps
- Alchemy: Hellenistic and Medieval Alchemy
- Alchemy: Indian Alchemy
- Alchemy: Islamic Alchemy
- Alchemy: Renaissance Alchemy
- Alcock, Sir John William
- Alexander Nevski, Saint
- Alexanderson, Ernst Frederik Werner (1878–1975)
- Alexandrian school
- Álfar
- Alfasi, Yits?aq ben Ya?aqov
- algebraic operation
- Algicide
- Alinesitoue
- Alkalai, Yehudah ben Shelomoh
- All Blacks
- All Fools' Day
- All-Father
- Alligator Lizards, Galliwasps, Glass Lizards, and Relatives (Anguidae)
- Alligator, American
- Alligators and Caimans (Alligatoridae)