- Asterisk
- Asterism
- Asteroid
- Asthmatic
- Astigmatism
- Astonishment
- Astound
- Astral
- Astro
- Astrobotany
- Astrolabe
- Astrological
- Astrology
- Astronomer
- Astronomical
- Astrophysics
- Asunder
- Aswamedha
- Asylum
- Asymmetry
- At a snails pace
- At peace
- At rest
- At school
- At the drop of a hat
- At the end of the tether
- At the full
- At the sea
- At the wicket
- Atomizer
- Atrium
- Atrocity
- Attache
- Attainability
- Attainable
- Attainment of manhood
- Attempt
- Auberge
- Audacious
- Audible
- Audiology
- Audiometer
- Audiovisual
- Auditory
- Augean
- August
- Augustan
- Auld
- Auld lang syne
- Authorship
- Auto
- Auto score
- Auto-suggestion
- Autocracy
- Autogenously
- Autolysis
- Automatic
- Automatic check
- Automaton
- Automobile
- Avocado
- Avocation
- Avoidable
- Avoidance
- Avoiding
- Avow
- Awaken
- Awakened
- Aware
- Away
- Awed
- Awkwardness
- Awning
- Agoraphobic
- Avoirdupois
- Amaranthus
- Antiquary
- Auctor
- A bad pill to swallow
- A bed of roses
- A bird in hand is worth two in the bush
- A bit much
- A blood relative
- A cardinal error
- A dead duck
- A dead luck
- A dear john letter
- A disciple who lodges with his preceptor
- A divine ministrel
- A dogs life
- A dry
- A false alarm
- A fiche
- A fish
- A floating voter
- A form of verse in which each line contains eight letters
- A golden parachute
- A good innings
- A good thing
- A grain of paddy