Dictionaries, Thesauruses, Pictures, and Press Releases
- Arkell, William Joscelyn
- arkosic arenite
- arkosic wacke
- arls
- Armadillidae
- Armillaria
- Armillaria mellea
- armoured catfish
- Armstrong, Edward Frankland
- Armstrong, Henry Edward
- army ant
- army worms
- Arnold, Harold De Forest
- Arnsbergian
- arolium
- Aromadendron
- Aromatari, Giuseppe Degli
- Aronhold, Siegfried Heinrich
- Arowhanan
- Arrest, Heinrich Louis D’