- Ant-lion
- Antagonism
- Ante-mortem
- Antecedent
- Antedate
- Antediluvian
- Antelope
- Antemeridian
- Antenatal
- Anthem
- Antherdiopore
- Anthracite
- Anthrax
- Anthropogenic
- Anthropography
- Anti lice
- Anti-semite
- Anyhow
- Anything visible
- Anywhere
- Aorta
- Ap
- Apace
- Apart
- Apartheid
- Apartment
- Apeman
- Aphasia
- App
- Appealing
- Appearing
- Appease
- Appeased
- Appendectomy
- Appetence-cy
- Appetizer
- Applause
- Applicant
- Application software
- Applied
- Applique
- Apply
- Appoint
- Appointment
- Appologised
- Appoointed
- Apportioning
- Apportionment
- Appose
- Appraisable
- Appraisee
- Appreciably
- Appreciate
- Aptly
- Aqua regia
- Aquaculture
- Arab
- Arabian jasmine
- Arbiter
- Arbitral
- Architrave
- Archivolt
- Archon
- Ardor
- Ardour
- Argentine
- Argosy
- Arguable
- Argue
- Argus
- Arid
- Arise
- Arisen
- Aristocracy
- Arithmetic
- Arithmetic progression
- Arithmetical progression
- Armada
- Armadillo
- Armature
- Armchair
- Armed
- Armed neutrality
- Armenius
- Armhole
- Armoire
- Armour
- Armour-plated
- Arrogant person
- Arrogantly
- Arrow-root plant
- Arrowhead
- Arrowroot
- Arsenal
- Arsonist
- Art of war
- Artefact
- Artful
- Article
- As common as much