- Acquired taste
- Acquit oneself well
- Acquitted
- Acreage
- Acrochordon
- 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
- Antagonize
- Antarctic
- Ante
- Anvil
- Anteroom
- Anthers
- Anthill
- Anthology
- Anthropic
- Anthropoid
- Anti-tank
- Antianxiety
- Antichthon
- Anticipate
- Anticipating
- Anticipatory
- Anticyclone
- Antifoundationalism
- Antihero
- Antilogy
- Antimycotic
- Antinational
- Antique
- Anxiously
- Any eye-salve
- Any more
- Anybody
- Anyone
- Anything real
- Anytime
- Aortal
- Apart from
- Ape
- Aperitif
- Apheresis
- Aplasia
- Aplenty
- Apocalyptic
- Apolitical
- Apologue
- Apoplectic
- Apostatize
- Apostrophe
- Apotheosis
- Appal
- Appall
- Appallingly
- Apparent
- Apparition
- Appear
- Appellate
- Appendage
- Appendix
- Apperception
- Appetising
- Appetitive
- Appetizing
- Apple
- Applet
- Appleton layer
- Applicable
- Application window
- Applicator
- Appointed
- Appointed time
- Apposite
- Apposition
- Appraisal
- Appraised
- Appreciation
- Appreciator
- Apprehensive
- Apprenticed
- Appress
- Approaching
- Approching
- Appropriate
- Approval
- Approximately