- area exchange
- area graph
- argument principle
- Aristotelian logic
- arithmetic comparison
- arithmetic division
- arithmetic exception
- arithmetic instruction
- arithmetic section
- arithmetic shift
- arithmetic symmetry
- arithmetic type
- arithmetical circuit
- arithmetical invariant
- arithmograph
- armoured concrete
- array declarator
- array file
- array parameter
- array pointer
- array type
- arrow key
- articulated joint
- artificial selection
- aspect ratio
- asphericity
- assemble origin
- assembler language
- assembler routine
- assembly listing
- assembly program
- assignable
- assignment operator
- associate matrix
- associated element
- associated matrix
- association factor
- associative array
- associative relation
- associativity
- astable circuit
- astronomical
- astronomical latitude
- astronomical triangle
- asymmetric device
- asymptotic circle
- asymptotic density
- asymptotic expansion
- asymptotic slope
- asymptotically
- asynchronous
- asynchronous exit
- asynchronous modem
- asynchronous request
- at
- atlas sheet
- atomic operation
- atomic proposition
- atomicity
- attach
- attach-ability
- attachable
- attached processing
- attaching device
- attachment
- attachment feature
- attack
- attack director
- attack pattern
- attainable accuracy
- attended operation
- attended time
- attention interruption
- attenuation
- attenuation distortion
- attenuation equalizer
- attenuation factor
- attenuation network
- attenuation ratio
- attenuator
- attic joist
- attractive factor
- attractiveness
- attractor
- attribute byte
- attribute data
- attribute definition
- attribute elements
- attribute file
- attribute key
- attribute list
- attribute relationship
- attribute simulation
- attribute specification
- attribute table
- attribute type
- attribute-value
- audio amplifier
- audio codec
- audio dithering