- At peak
- At play
- At sea
- At sixes and sevens
- At stake
- At the eleventh hour
- At the longest
- At the same time
- At the top of ones voice
- Atone
- Atonement
- Atrocious
- Atrocities
- Atrorcious
- Attaching
- Attachment
- Attachments
- Attacker
- Attain
- Attempt the impossible
- Auctioneer
- Audibility
- Audibleness
- Audibly
- Audit
- Audition
- Auditor
- Aught
- Augmented reality
- August-september
- Augustly
- Autopsy
- Autotype
- Autumn
- Avacado
- Avarise
- Aver
- Average
- Avid
- Avidly
- Aviform
- Axle-tree
- Azolla
- Azure
- Adp
- Airily
- A plant with sweet-scented roots
- A plum job
- A pretty kettle of fish
- A pretty penny
- A quixotic project
- A variety of sida
- A safe pair of hands
- A sea of
- A shot in the arm
- A shot in the locker
- A signal achievement
- A sorry sight
- Abnormally
- Abode assylum
- Abolishment
- Abolitionism
- Abolitionist
- Abominable snowman
- Abomination
- Aboriginal
- Abreaction
- Abortive
- Abounding in waves
- About-face
- About-turn
- Above
- Above ones head
- Above ones reach
- Absently
- Absolute
- Aqiqah
- Absorb in
- Absorbed
- Absorbent
- Absorbing
- Abstract art
- Abstractedness
- Accent
- Acceptableness
- Access mode
- Accessary
- Accession
- Accessory
- Accessory gland
- Accident
- Accident-prone
- Acclimatized
- Acclivity
- Acculturation
- Accumulation
- Accumulative
- Accuse
- Accused
- Accute angle