- A stroke of fate
- A thing or two
- A think tank
- A thorny question
- A tree which has shed its leaves
- A tune
- A type of plantain
- A water grass with umbrella-like foliage
- Aasvogel
- Absentation from mention
- Absolute majority
- Absolute ruler
- Absolution
- Absolve
- Absorber
- Abstain
- Abstention
- Abstract
- Accentuate
- Accessed
- Accidental
- Accidentality
- Acclamatory shouting
- Acclimatization
- Accommodation
- Accompaniments
- Accomplish
- Accomplished
- Accomplishment quotient
- Accordant
- Accorded
- Accordingly
- Accountrements
- Accounts payable
- Accounts receivable
- Accoustics
- Acetic acid
- Ache
- Acid lemon
- Acidophilus
- Acidulous
- Acknowledge
- Acknowledged
- Acm
- Acne
- Acorn
- Acoustic
- Act of peace
- Action meter
- Action-packed
- Activate
- Active server pages
- Active service
- Active voice
- Actively
- Activeness
- Activewear
- Actress
- Actual
- Actualise
- Add on
- Add up
- Addicted
- Addictive
- Adding
- Additional
- Addle
- Addled
- Address field
- Addressee
- Adduce
- Adhere
- Adhering
- Adjacent
- Adjoin
- Adjudge
- Adjudication
- Adjudicator
- Adjunct
- Adman
- Administer
- Administrating
- Administration
- Administrative
- Administrative system
- Admire
- Admiring
- Admissibility
- Admission
- Admitted
- Admixture
- Admonishment
- Adnation
- Ado
- Adobe
- Adopt
- Adoptive
- Adore
- Adventuress
- Adverb