Encyclopedias, Almanacs, Transcripts, and Maps
- Arctic Council
- Arctic Haze
- Arctic National Wildlife Refuge
- Arctic Religions
- Arctic Religions: An Overview
- Arctic Religions: History of Study
- Arctic tern
- Arhat
- Arid Climates
- Arid Landscaping
- aristocratic ranks (UK)
- Ark of the Covenant
- Armadillos (Dasypodidae)
- Armenian Religion
- Armistice Day
- Army Corps of Engineers
- Army, British
- Army, US
- Arnold, Sir Malcolm
- Arrhenius, Svante August (1859 – 1927) Swedish Chemist and Physicist