- anomia
- American Standard Code for Information Interchange
- anagnost
- answerableness
- answerability
- American state
- accountability
- apocrine gland
- abdominal respiration
- american virgin islands
- an enemy
- a hostile person
- adrianople
- adrianopolis
- anastigmat
- anopia
- arm_twisting
- a firm hand
- a splashing sound
- an important hindi poetic metre running into six lines
- a thatch
- abhorrence
- aeschylean
- aphasia
- ataxic aphasia
- art exhibition
- aerial ladder
- abdominal breathing
- applauder
- angle of extinction
- anisometropia
- ambiversion
- ambiversive
- acre inch
- acre_foot
- atomic mass unit
- allocation structure
- allocheiria
- anaglyph
- a thin crust
- aureate
- arabian nights
- arabian nights' entertainment
- a vagabond
- anxiety attack
- Anisoptera
- Amoebida
- Alcyonaria
- Araneae
- Actiniaria