- attribution
- attrition mill
- attrition vein
- attune
- auction
- audiobook
- audiometry
- auditor
- auditorium block
- augen-gneiss
- auger
- auger boring
- augering
- augite granite
- augment
- aural
- authority
- auto-crane
- auto-panning
- auto-trace
- autoclave box
- autoclave chamber
- autoclave digester
- autoclave hardening
- autoclave treatment
- autoclaving
- autodecrease
- autodyne
- automated cafe
- automated drawing
- automatic batcher
- automatic clutch
- audibility
- audible signal
- audience
- audio
- audio cassette
- audio frequency
- audio information
- auger stem
- augite syenite
- auriferous quartz
- austere
- auto arrange
- auto headlight
- autobiography
- autoclave
- autoclave cycle
- autoflow
- autoincrease
- automated system
- automatic bolting
- automatic bucket
- automatic centering
- automatic detection
- automatic discharge
- automatic float
- automatic formatting
- automatic compensation
- automatic control
- automatic reader
- automatic system
- automatic typewrite
- automation level
- auxiliary axis
- auxiliary building
- auxiliary crossbar
- auxiliary dam
- auxiliary diagonal
- auxiliary drive
- auxiliary gallery
- auxiliary handle
- auxiliary hoist
- auxiliary process
- auxiliary shoring
- auxiliary support
- auxiliary truss
- available application
- avalanche
- avalanche load
- avarice
- average
- average earnings
- average stress
- avoid
- awning window
- axial compression
- axial deformation
- axial expansion
- axial fan
- axial flow
- axial rotation
- axial stiffness
- axial surcharge
- axial tension
- axisymmetrical
- axle load
- axle unit
- azimuth closure
- automatic turning