- Armageddon
- Armament
- Armful
- Armless
- Armored
- Armorer
- Armory
- Arrows
- Arse over tit
- Arsenic
- Arsis
- Arson
- Art
- Art of creating new meaning by deleting one word
- Art work
- Artesian well
- Articles
- As far as in me lies
- As follows
- As gay as a lark
- As it were
- As much
- As much as
- As never before
- Asphalt
- Asphyxia
- Asphyxiator
- Aspirate
- Aspiration
- Aspire
- Asr
- Ass
- Assailant
- Assassin
- Assort
- Assuage
- Assumed
- Assumed name
- Assuming
- Assumption
- Assylum
- Astadyayi
- Asthma
- Astir
- Astral projection
- At ones wits end
- At par
- At point blank range
- At short notice
- At temper
- At the hand of
- At the moment
- At the old school
- At the top of the tree
- Atomize
- Atop
- Atrophy
- Ats
- Attache case
- Attached
- Attacking
- Attagirl
- Attained
- Attaining
- Attainment
- Attempt on the life of
- Au revoir
- Auburn
- Audacity
- Audience hall
- Auditorium
- Auspiciousness
- Auger
- Augment
- Augural
- Auhenticating
- Auxiliary
- Avant-garde
- Avaricious person
- Avascular
- Avengeful
- Aversion
- Aversion therapy
- Avian influenza
- Ayacut
- Ayatollah
- Aye
- Ayurvedic treatment
- Ayyappa
- Azimuth
- Azotemia
- Absolutist
- Aero
- A
- A bad patch
- A bed of thorn
- A big name
- A bird in the hand is worth two in the bush
- A bit thick
- A capital offence