- backing strip
- backing up
- backjoint
- backlog maintenance
- backpack
- backplane
- backplastering
- backplate
- backpressure
- backpropping
- backsaw
- backset
- backshoe shovel
- backsight
- backspace key
- backstage
- backtrack
- backup
- backup strip
- backward pass
- backwash
- backwater
- backwater area
- backwater curve
- backwater length
- backwater storage
- backwater structure
- backwater valve
- backwater zone
- automatic heating
- automatic level
- automatic loader
- automatic mixing
- automatic scale
- automatic siphon
- automatic sprinklers
- automatic switch
- automatic tachometer
- automatic tongs
- automobile traffic
- autonomy
- autopilot
- autostable
- auxiliary angle
- auxiliary contour
- auxiliary device
- auxiliary farm
- auxiliary staircase
- auxiliary structure
- available head
- avalanche dike
- avalanche gallery
- avenge
- avenue
- average annual
- average illuminance
- averaging
- axe
- axhammer
- axiom
- axiomatic semantics
- axonometric view
- azonality
- azure blue
- bachelor house
- bachyaxial fold
- back arch
- automatic feed
- automatic gate
- automatic locking
- automatic stop
- automatic weir
- automotive
- autostability
- autostressing
- await
- axial displacement
- axial strain
- axle
- axle loading
- axonometric
- azimuth clamp
- azimuthally motion
- bacterial pollution
- bactericidal irradiation
- bactericidal lamp
- bactericidal plant
- bactericidal radiation
- bactericidity
- bad
- bad ground
- bad sheet
- bad stylization
- badger
- badger softener
- baffle
- baffle beam
- baffle brick
- baffle pier
- baffle plate