- Aril
- Arithmetically
- Arithmetician
- Arjuna
- Armband
- Armlet
- Armoured
- As and when
- Arms
- Army corps
- Aroma
- Aromatic
- Arpeggio
- Arrange
- Arrest
- Arrest attention
- Arrhythmic
- Arrived
- Arrogant
- Arrogate
- Arrow
- Arrow and bow
- Arrow point
- Arrow-root flower
- Arrow-root powder
- Arrow-root-flour
- Art director
- Arthropod
- Articulation
- Artificial respiration
- Artificialness
- Artist
- Artiste
- Artistic
- Artless
- Arts and part
- Arya race
- As clear as mud
- As far as possible
- As fit as a fiddle
- As if
- As memory serves
- As much again
- As old as methuselah
- As one man
- Asian
- As the crows fly
- As though
- As well
- As yet
- As you sow so you reap
- Ascariasis
- Ascendant
- Askant
- Asked
- Asking
- Aslant
- Asleep
- Aspects
- Aspersion
- Assafoetida
- Assail
- Assam
- Assassinate
- Assault
- Assay
- Assured
- Asthenia
- Astis
- Astonished
- Astraddle
- Astral body
- Astray
- At all costs
- At all times
- At close quarters
- At dawn
- At full pelt
- At full strain
- At hand
- At knife point
- At length
- At will
- Atelophobia
- Atheism
- Atheistic
- Athri
- Athwart
- Atlantic
- Atmosphere
- Atom
- Atomic
- Atomic number
- Auctioneer
- Audibility
- Audibleness
- Audibly
- Audit
- Audition
- Auditor