- Abiotic
- Abjuration
- Able
- Able-bodied
- Ably
- Abrachia
- Abraham
- Abrasive
- Abridgement
- Abroad
- Abrogate
- Abrogation
- abrus precatorius
- Abscess
- Abscission
- Absurdly
- Abundant
- Abuse
- Abusive
- Abyss
- Abyssal
- Acacia adoratissima
- Acacia intsia
- Academia
- Academy
- Acarpous
- Accede
- Accelerate
- Accelerator
- Accompany
- Accomplishing
- According
- According to
- According to ones lights
- According to schedule
- Accoucheuse
- Account
- Account for
- Accountability
- Accountable
- Accounting
- Accounts
- Accoutrements
- Accredit
- Achievement quotient
- Achilles heel
- Aching
- Achy
- Acid test
- Acidity
- Acknowledgement
- Acknowledgment
- Acolyte
- Acoustics
- Acquaintances
- Act up to
- Acting
- Actinic
- Actinotherapy
- Action plan
- Actions
- Actions speak louder than words
- Activation
- Active and passive voices
- Activex
- Actuality
- Acute-angled cucumber
- Acuteness
- Ad
- Ad interim
- Ad valorem
- Adam's apple
- Adamantly
- Adaptability
- Add to
- Addenda
- Additionally
- Address size
- Adenoids
- Adept
- Adequacy
- Adhatoda vasica
- Adherent
- Adiabatic
- Adieu
- Adipose
- Aditya
- Adjourn
- Adjutant
- Administratively
- Administrator
- Admirably
- Admiralty
- Admire for
- Admired
- Admissible
- Admittedly
- Admix
- Admonish
- Adolescence