- Atheism
- Atheistic
- Athri
- Athwart
- Atlantic
- Atmosphere
- Atom
- Atomic
- Atomic number
- Atone
- Atonement
- Atrocious
- Atrocities
- Atrorcious
- Attaching
- Attachment
- Attachments
- Attacker
- Attain
- Attempt the impossible
- Attendant
- Attending
- Attentive
- Attestation
- Attractiveness
- Atwitter
- Au courant
- Auctioneer
- Audibility
- Audibleness
- Audibly
- Audit
- Audition
- Auditor
- Aught
- Augmented reality
- August-september
- Augustly
- Aunt
- Aureate
- Aurora
- Auster
- Austere
- Auteur
- Authenticate
- Authentication
- Authorised
- Authoritarianism
- Authoritative
- Authorized person
- Autistic
- Auto index
- Auto-ignition
- Autobiography
- Autodidact
- Automation
- Autonomy
- Autopsy
- Autotype
- Autumn
- Avacado
- Avarise
- Aver
- Average
- Avid
- Avidly
- Aviform
- Avionics
- Awake
- Awe
- Awe-inspiring
- Awestruck
- Awhile
- Awkwardly
- Awn
- Axle-tree
- Azolla
- Azure
- Absolvable
- Air
- Altaltissimo
- Ark
- Astron
- Ataxia, ataxia
- a bag of bones
- A bed roses
- A bird in a golden cage
- A bit
- A black sheep
- A black-leg
- A blank look
- A bull in a china shop
- A bun in the oven
- A capella
- A chorus of thanks
- A cold sweat
- A cubit
- A dirty trick
- A divine bird born of aruna and syeni
- A dog's death