- And that
- Andaman island
- Andragogy
- Androecium
- Andrology
- Angst
- Angular
- Angular diameter
- Aniconism
- Animal kingdom
- Animistic
- Anise seed
- Anise seed herb
- Annexe
- Anteroom
- Anthers
- Anthill
- Anthology
- Anthropic
- Anthropoid
- Anti-tank
- Antianxiety
- Antichthon
- Anticipate
- Anticipating
- Anxiously
- Any eye-salve
- Any more
- Anybody
- Anyone
- Anything real
- Anytime
- Aortal
- Apart from
- Ape
- Aperitif
- Appal
- Appall
- Appallingly
- Apparent
- Apparition
- Appear
- Appellate
- Appendage
- Appendix
- Apperception
- Appetising
- Appetitive
- Appetizing
- Apple
- Applet
- Appleton layer
- Aptitude
- Aptness
- Aqua
- Aquamarine
- Aquaphobia
- Aquarius
- Aquatic
- Aqueous
- Aquifer
- Arabia
- Arabic
- Arak
- Arbitrary
- Arbor
- Arcot
- Arcturus
- Are
- Area code
- Arena
- Areola
- Argania
- Argon
- Armoury
- Armpit hair
- Arms race
- Army
- Arouses
- Arrack
- Arras
- Array
- Arraying
- Arrear
- Arrive
- Arrogance
- Articles of association
- Articulated
- Artillary
- Artilleryman
- Artiodactyl
- Artocarpus heterophyllus
- Artocarpus hirstula
- Arundhati star
- As a result of
- Ascending
- Ascending node of caput draconis
- Ascii
- Ascription
- Aseity