- Anticoagulant
- Antidemocrat
- Antidote
- Antifreeze
- Antigen
- Antiperspirant
- Antiphon
- Antiseptic
- Antisocial
- Ants
- Ants in ones pants
- Antsy
- Anxiety disorders
- Any
- Any day now
- Anyplace
- Anything but
- Anything small
- Anyway
- Aourora
- Apathy
- Apepsy
- Aperture
- Apex
- Aphid
- Aphrodisiac
- Apiology
- Apnoea
- Apocryphal
- Apodyopsis
- Apogee
- Apology
- Apophenia
- Apophysis
- Apoptosis
- Aporia
- Apostasy
- Apostate
- Appalled
- Appalling
- Apparently
- Appeal
- Appearance
- Appeasement
- Append
- Applaud
- Apple-pie order
- Aria
- Applicability
- Application form
- Applies
- Applying
- Appointee
- Apportion
- Appraise
- Appraisement
- Appreciable
- Appreciated
- Apprehensible
- Appropriately
- Appropriateness
- Appropriation
- Approver
- Approximate
- Appulse
- Appurtenance
- Apron
- Apsidiole
- Aptitude test
- Aqua-lung
- Aquaponics
- Aquaris
- Aquarist
- Aquarium
- Aqueduct
- Aquiline
- Arab colonist
- Arabian
- Arabian sea
- Arable
- Arbitrate
- Arbitration
- Arbitrator
- Arbitrators
- Arbour
- Arc
- Arch-vault
- Archdeacon
- Archdiocese
- Archer
- Archetypal
- Archfiend
- Architect
- Architectonic
- Architectural
- Archway
- Arctic
- Arctic pole
- Ardent desire
- Ardent spirits