- Apparent
- Apparition
- Appear
- Appellate
- Appendage
- Appendix
- Apperception
- Appetising
- Appetitive
- Appetizing
- Apple
- Applet
- Appleton layer
- Appreciator
- Apprehensive
- Apprenticed
- Appress
- Approaching
- Approching
- Appropriate
- Approval
- Approximately
- Approximation
- Apricot
- Apt
- Arboretum
- Arcane
- Arch-rival
- Archaeologist
- Archbishop
- Archery
- Architecturally
- Arian
- Aries
- Aristocrat
- Aristocratic
- Arithmetical
- Armed guard
- Armed to the teeth
- Armistice
- Arrow-tip
- Art of arms
- Art of dancing
- Art paper
- Artefactual
- Artery
- Arthritis
- Artichoke
- Artichokes
- As free as air
- As helpless as a babe
- As i see it
- As it comes
- As it stands
- As keen as mustard
- As large as life
- As many
- As matter of
- As much as possible
- As of
- Ascending
- Ascending node of caput draconis
- Ascii
- Ascription
- Aseity
- Asepsis
- Ash
- Ash wednesday
- Ash-gourd
- Ask for a blank cheque
- Ask for the moon
- Assembling
- Assertion
- Assessment
- Assets
- Assignation
- Assignee
- Assimilation
- Assist in
- Associates
- Association
- Astrogeology
- Astroid
- Astrologers
- Astronaut
- Astrophysicist
- Asvamedha sacrifice
- Asymmetrical
- Asymptote
- At a loose end
- At a price
- At a run
- At this rate
- At time
- At war
- Atavism
- Ate
- Atheist
- Atlas
- Atoll