- backout
- backrolling
- backscattered
- backscattered ion
- backscattering angle
- backup arrangement
- backup protection
- backup relay
- backward lead
- backward shift
- automatic purge
- automatic purging
- automatic refrigeration
- automatically operated
- automatics
- auxiliary air
- availability ratio
- avalanche breakdown
- avalanche photodetector
- avalanche transistor
- avalanche-like
- axial clearance
- b phase
- automatic operation
- automatic timer
- automatic trap
- autooscillation
- autoradiography
- axial lead
- azeotropic point
- bacterial spoilage
- bacteriological study
- baffle
- bag filter
- Bailey beads
- bakelized
- bakery froster
- baking varnish
- balance coil
- balanced conditions
- balanced converter
- balanced currents
- balanced line
- balanced pair
- balanced voltages
- balancer
- balancing bellows
- balancing unit
- ball-shaped
- ballast
- ballast factor
- ballast lamp
- ballast resistor
- ballastic
- ballastic galvanometer
- ballastic pendulum
- balloon
- banana pin
- banana plug
- band head
- band model
- band pattern
- band spectrum
- banded absorption
- banding
- bandspread
- bandwidth
- bank
- base load
- base vector
- base-centered
- basic noise
- batch operation
- bath cryostat
- bathtub capacitor
- beam efficiency
- bar
- barrel winding
- barrel-shaped
- barretter
- barring gear
- barycenter
- baryon decuplet
- baryonic spectroscopy
- baryonic state
- beam valve
- beam width
- beat
- beavertail
- bedspring array
- beer cooler
- bell transformer
- belt
- bar suspension
- bar winding
- bare conductor
- barium titanate
- Barlow lens
- Barnett method
- barograph