- autotoxin
- autotrophic-baterium
- auxilytic
- auxocyte
- avena flavescens
- aversion therapy
- avitaminosis
- axillary vein
- axonal degeneration
- axoplasm
- azapetine
- azotaemia
- babies care
- bacillary
- bacillemia
- bacilliculture
- bacillogenic
- bacilloscopy
- bacitracin
- back
- back knee
- back reef
- back rest
- back-cross
- backbone
- backflow
- backing
- backward progression
- automatic writing
- automatism
- autonarcosia
- autonomotropic
- autopathy
- autopsy room
- autosuggestion
- autotroph
- auxo-cardia
- auxotroph
- avena
- axial angle
- axial neuritis
- axial surface
- azoturia
- azygos vein
- babesiasis
- baciliuria
- bacillicidal
- bacilliform
- bacilliparous
- bacillosis
- bacillus
- autopolymer resin
- autoptical
- autospermotoxin
- autotoxication
- autotransfusion
- autotrophic organism
- axial myopia
- axillarry line
- azathloprine
- bacon spleen
- bacteremia
- bacterial allergy
- bacterial enzyme
- bacterial spore
- bacterial therapy
- bactericidal
- bactericidal antibiotic
- bactericidal ray
- bacterid
- bacteriform
- bacterin
- bacterio-agglutinin
- bacteriocidin
- bacteriolysin
- bacteriolysis
- bacteriolytic amboceptor
- bacteriopexy
- bacterioprecipitin
- bacterioscopy
- bacteriosis
- bacteriostatic
- bacteriostatic antibiotic
- bacteriotherapy
- bacteriotoxin
- bacteriotropic
- bacteroides
- badger leg
- baffle
- bahaviour therapy
- balanced occlusion
- balanced-anesthesia
- balanitis
- balanoposthitis
- balantidiasis
- baldness
- ball
- ball myoma
- ballismus
- ballistocardiograph