- attitude acquisition
- attitude display
- attitude fitter
- attitude hold
- attitude motion
- attitude sensing
- attitude sensor
- attitude signal
- attitude stabilization
- attitude updating
- attributable expenditures
- attribute byte
- attribute simulation
- audibble beats
- audibble effect
- audio band
- audio-track
- audit certificate
- auroral hiss
- auroral zone
- authorized library
- authorized user
- auto dial
- automated office
- automatic carriage
- automatic changeover
- audible sound
- audio communication
- audio frequency
- audio stream
- audio-spectrum
- audio-system
- audited accounts
- aural monitoring
- aural reception
- auroral blackout
- auroral disturbances
- authorization check
- automated graphics
- automatic acknowledgement
- automatic carrier
- automatic coding
- automatic drive
- automatic equalizer
- automatic exchange
- automatic iris
- autopilot system
- autotrack antenna
- auxiliary register
- available point
- available power
- available resources
- available state
- average delay
- average error
- average ground
- averaging device
- averaging filter
- averted side
- aW
- axial rate
- azimuth plane
- auxiliary rocket
- auxiliary transmission
- average logarithm
- average price
- azimuth scale
- B-channel
- B-modulation
- Babcock plan
- baby spot
- back coupling
- back level
- back porch
- back scattering
- back signal
- back-streaming
- backfire antenna
- background emission
- background illumination
- background light
- background noise
- background printing
- background reader
- background region
- backing storage
- backing store
- backout
- backplane
- backscatter distance
- backscattering coefficient
- backscrolling
- backup procedure
- backup system
- backup time
- backward difference
- backward diode
- backward indicator
- backward pointer
- backward processing