- antenna reorientation
- antenna steerability
- antenna system
- anti-vibration
- angle factor
- angle modulation
- angular degree
- angular displacement
- angular size
- angular variation
- anisotrophie
- annotation symbol
- amplification coefficient
- amplifier bandwidth
- amplifying stage
- amplitude analysis
- amplitude assessor
- amplitude demodulation
- amplitude noise
- amplitude ratio
- analog environment
- analog information
- analog recording
- analog transmission
- analogue machine
- analogue representation
- analogue signal
- analysis filter
- analysis routine
- analytic engine
- anamorphic film
- antenna attenuator
- antenna beam
- antenna circuit
- antenna configuration
- antenna diagram
- antenna directivity
- antenna director
- antenna duplexer
- antenna factor
- antenna mast
- antenna matching
- antenna output
- antenna pattern
- antenna plant
- antenna polarization
- antenna reflector
- antenna spacing
- antenna temperature
- anticipatory paging
- antifading antenna
- anechoic chamber
- angular modulation
- angular refraction
- angular zone
- antenna axis
- antenna deck
- antenna loading
- antenna mount
- antenna programmer
- antigravity
- antiphase
- antiral compound
- antisunward
- apastron
- aperiodic antenna
- aperture admittance
- aperture antenna
- aperture blockage
- aperture coupling
- aperture distortion
- aperture effect
- aperture efficiency
- aperture field
- aperture illumination
- aperture impedance
- aperture mask
- aperture plane
- aperture vector
- apillover radiation
- apoapsis
- apogee
- apparent disk
- apparent gain
- apparent gravity
- apparent noon
- apparent output
- apparent position
- apparent resolution
- application layer
- application problem
- application profile
- application satellite
- application service
- approach zone
- appropriation line
- approving officer
- apsidal propulsion
- arc second
- area function