- arboriculturist
- apiculturist
- agriculture engineer
- agrarian
- aquiculture
- arboriculture
- andrew carnegie
- argali
- argal
- aoudad
- Ammotragus lervia
- arui
- audad
- albrecht durer
- arum family
- aroideae
- araceous
- arulo
- administrative law
- Archimedes' principle
- Alces alces
- aggrieve
- amenhotep iv
- actual data transfer rate
- a mischief_maker
- Addax nasomaculatus
- Adenota vardoni
- Antilope cervicapra
- antelope chipmunk
- asafetida
- acaroid resin
- accroides gum
- accroides resin
- accroides
- accaroid resin
- ambrogio damiano achille ratti
- agavaceae
- almost free
- accusal
- anemone fish
- Abudefduf saxatilis
- alfred de musset
- apache devil dance
- ablative absolute
- a russian
- acquired immune deficiency syndrome
- AIDS
- acute anterior poliomyelitis
- Asiatic cholera
- adulterator