- Asura
- as usual
- ASW
- Aswan
- Aswan Dam
- Aswan High Dam
- aswarm
- as well
- as well as
- aswirl
- aswoon
- as yet
- asylee
- asyllabic
- asylum
- asylum seeker
- asymmetric
- asymmetrical warfare
- asymmetric bars
- asymmetric slow-wave sleep
- asymmetric time
- asymmetric warfare
- asymmetry
- asymptomatic
- asymptote
- asymptotic
- asymptotically
- asymptotic freedom
- asynapsis
- asynchronism
- asynchronous
- asynchronous transmission
- asyndetic
- asyndeton
- asynergia
- asynergy
- Asynjur
- asyntactic
- As You Like It
- as you please
- asystole
- Asyut
- asˈcetiˌcism
- Asˈsyrian
- asˈtronomer
- at
- aT
- At
- AT
- at-
- At/m
- at.
- at. no.
- ataata
- at about
- Atabrine
- Atacama Desert
- atacamite
- atactic
- at a discount
- ataghan
- Atahualpa
- Atakapa
- Atalanta
- at all
- at all costs
- at all times
- at a loss
- at a low ebb
- ataman
- atamasco lily
- at any cost
- at any rate
- at a premium
- ataractic
- Atarax
- ataraxia
- at arm's length
- Atascadero
- at a sitting
- at a stretch
- at a time
- Atatürk
- Ataturk, Kemal
- atavic
- atavism
- atavistic
- at a word
- ataxia
- ATB
- Atbara
- at bat
- at bay
- at best
- at bottom
- ATC
- Atchafalaya
- Atchison
- at close quarters
- at close range
- at cross purposes
- at death's door
- at-desk
- ate
- Ate
- ATE
- at each other's throats
- A Team
- at ease
- Atebrin
- atef-crown
- atelectasis
- atelier
- ateliosis
- atemoya
- a tempo
- atemporal
- Aten
- Aten asteroid
- atenolol
- a tergo
- Aterian
- à terre
- at every turn
- at face value, take
- at fault
- at first
- at first blush
- at first hand
- at full tilt
- Atget
- at gunpoint
- Athabasca
- Athabascan
- Athabaska
- Athabaskan
- at half-mast
- Athaliah
- Athamas
- athame
- athanasia
- Athanasian
- Athanasian Creed
- Athanasius
- at hand
- athanor
- Athapascan
- Atharva-Veda
- at heart
- atheism
- atheist
- atheistic
- Athel
- atheling
- Athelstan
- athel tree
- athematic
- Athena
- athenaeum
- Athenaeum
- Athenaeus
- Athenaeus of Attaleia
- Athenagoras I
- Athenian
- Athénienne
- Athens
- atheoretical
- atherectomy
- atherine
- athermancy
- athermanous
- athero-
- atherogenic
- atheroma
- atherosclerosis
- Atherton
- athetosis
- A thing of beauty is a joy forever
- athirst
- athleisure
- athlete
- athlete's foot
- athlete's heart
- athletic
- athletically
- athleticism
- athletics
- athletic shoe
- athletic support
- athodyd
- Athol
- Atholl brose
- at home
- at-home
- athonite
- Athos
- athrill
- athrocyte
- athwart
- athwartships
- atigi
- atilt
- A time to be born and a time to die
- atingle
- atiptoe
- atishoo
- at issue
- at it
- Atitlán
- Ativan
- ATK
- Atka Island
- Atka mackerel
- Atkins
- Atkinson
- Atl.
- Atlanta
- atlantal
- Atlantean
- atlantes
- Atlantic
- Atlantic Charter
- Atlantic City
- Atlantic Intracoastal Waterway
- Atlanticism
- Atlanticist
- Atlantic Ocean
- Atlantic Provinces
- Atlantic salmon
- Atlantic Standard Time
- Atlantic time
- Atlantis
- at large
- atlas
- Atlas
- Atlas cedar
- Atlas Mountains
- at last
- atlatl
- at law
- at least
- at leisure
- at length
- Atli
- at liberty
- at loggerheads
- at long last
- at loose ends
- ATM
- atm.
- atman
- atmo-
- atmolysis
- atmometer
- atmometry
- atmophile
- Atmos clock
- atmosphere
- atmospheric
- atmospheric braking
- atmospheric electricity
- atmospheric engine
- atmospheric perspective
- atmospheric pressure
- atmospheric river
- atmospherics
- atmospheric tide
- atmospheric window
- atmospherium
- at most
- ATN
- ATO
- at odds
- A to J
- atole
- atoll
- atom
- atom-bomb
- atomic
- atomic age
- atomic bomb
- atomic clock
- atomic cocktail
- atomic energy
- Atomic Energy Authority
- Atomic Energy Commission
- atomic force microscope
- atomic heat
- atomic hydrogen
- atomicity
- atomic mass
- atomic mass unit
- atomic number
- atomic pile
- atomic power
- atomics
- atomic spectrum
- atomic structure
- atomic theory
- atomic veteran
