- arrogant person
- arrow
- arrowroot
- arsis
- artificial intelligence
- artificial respiration
- artillery
- artilleryman
- artist
- artiste
- as and when
- as common as muck
- as thin as a lath
- as well as
- ascc
- ascending node of caput draconis
- asian palm civet
- asinine
- ask
- askance
- assail
- assamese
- assassin
- assemblage
- assembly
- assert
- assize
- assorted
- assuage
- astounding
- astroid
- astrolobe
- astronaut
- astronomer
- astute
- at a loose end
- at a price
- at a snails pace
- at first light
- at heart
- at length
- at liberty
- at present
- at the ready
- at the same time
- atfull tilt
- atheism
- athenaeum
- atherosclerosis
- athletic
- athri
- atomic energy
- attainable
- attempt on the life of
- attend
- attendance
- attraction
- attribution
- attrition
- attune
- auburn
- august
- aura
- aural
- aureus
- auspicious
- authorised
- authoritarian
- auto-ignition
- auto-typography
- autocracy
- autocratic
- avalanche
- avant-garde
- averse
- aversion therapy
- award
- awareness
- awash
- away
- awfully
- awhile
- awkward age
- abort
- abrogation
- absent-minded
- absorbing
- abstruse
- abstracted
- abundant
- abysmal
- acceptable
- accent
- accidental
- acclimatize
- accord
- account for
- accountability
- acknowledgement
- acquaint