China 
Africa 
- Adaptive management
- Adaptive optics
- Adaptive quadrature
- Adaptive reuse
- Adaptive sampling
- Adaptive simulated annealing
- Adaptive step size
- Adaptive stepsize
- Adaptive systems
- Adaptive user interface
- Adaptor proteins
- Add-drop multiplexers
- Added mass
- Added sugar
- Adder
- Adder-subtractor
- Addition
- Addition polymers
- Addition reactions
- Addition theorem
- Addition-elimination reactions
- Additive
- Additive Schwarz method
- Additive effect
- Additive manufacturing file format
- Address space
- Addressing scheme
- Adductor brevis
- Adductor canal
- Adductor hiatus
- Adductor pollicis
- Adductor pollicis muscle
- Adductor tubercle
- Adefovir
- Adenine
- Adenocarcinoma
- Adenomas
- Adenosine
- Adenosine diphosphate
- Adenosine kinase
- Adenosine monophosphate
- Adenosine receptor antagonist
- Adenosine receptors
- Adenosquamous carcinoma
- Adenoviridae
- Adenovirus
- Adenylation
- Adenylyl cyclase
- Adherence
- Adherens junctions
- Adherent culture
- Adhesins
- Adhesion
- Adhesion barrier
- Adhesion molecules
- Adhesion tester
- Adhesions
- Adhesive
- Adhesive bonding
- Adhesive tape
- Adhocracy
- Adiabatic
- Adiabatic circuit
- Adiabatic flame temperature
- Adiabatic process
- Adigrat sandstone
- Adipic acid
- Adipocytes
- Adipogenesis
- Adipokines
- Adiponectin
- Adiponitrile
- Adipose tissue
- Adipose tissue macrophages
- Adirondack
- Adjacency lists
- Adjacency matrix
- Adjacent channel
- Adjacent-channel interference
- Adjoint
- Adjoint equation
- Adjoint state method
- Adjusted mutual information
- Adjuvant therapy
- Adjuvants
- Administrative controls
- Admissible
- Admissible heuristic
- Admission control
- Admittance
- Admixture
- Adobe
- Adobe Acrobat
- Adobe Connect
- Adobe Illustrator
- Adobe Photoshop
- Adolescent idiopathic scoliosis
- Adomian Decomposition Method
- Adoptive cell transfer
- Adp-ribosylation
- Adrenal cortex
- Adrenal gland
- Adrenal medulla
- Adrenaline
- Adrenergic agonists
- Adrenergic receptors
- Adreno
- Adrenocorticotropic hormone
- Adsorbable organic halides
- Adsorbed natural gas
- Adsorption
- Adsorption refrigeration
- Adult neurogenesis
- Adult stem cells
- Adulterants
- Advance ratio
- Advanced Vector Extensions
- Advanced airway management
- Advanced automatic collision notification
- Advanced composite materials
- Advanced gas-cooled reactor
- Advanced glycation end-products
- Advanced manufacturing
- Advanced oxidation process
- Advanced packaging
- Advanced process control
- Advantage
- Advection
- Adventitia
- Adversarial machine learning
- Adversary
- Adverse drug reaction
- Adverse effects
- Adverse events
- Adverse outcome pathway
- Adverse pressure gradient
- Advice
- Adware
- Aegirine
- Aeolian
- Aeolian processes
- Aeolianite
- Aeon
- Aequorin
- Aerated lagoon
- Aeration
- Aerenchyma
- Aerial photography
- Aerial refueling
- Aerial survey