China 
Africa 
- Diorite
- Diosgenin
- Dioxane
- Dioxin
- Dioxins
- Dioxins and dioxin-like compounds
- Dioxolane
- Dioxygen
- Dioxygenase
- Dip
- Dip coating
- Dip slope
- Dip switches
- Dip-coating
- Dip-pen nanolithography
- Dipalmitoylphosphatidylcholine
- Dipamp
- Dipeptides
- Dipeptidyl peptidase
- Diphenyl carbonate
- Diphenyl ether
- Diphenylacetylene
- Diphenylalanine
- Diphenylamine
- Diphenylketene
- Diphenylmethane
- Diphosphine
- Diphosphine ligand
- Diphtheria
- Diphtheria toxin
- Dipicolinic acid
- Diplexer
- Diploid
- Diplopia
- Dipole
- Dipole antenna
- Dipyridamole
- Diquat
- Dirac comb
- Dirac delta function
- Dirac equation
- Dirac measure
- Dirac spinor
- Diradicals
- Direct air capture
- Direct analysis in real time
- Direct and indirect band gaps
- Direct bandgap
- Direct bonding
- Direct borohydride fuel cell
- Direct carbon fuel cell
- Direct chill casting
- Direct conversion receiver
- Direct coupling
- Direct digital control
- Direct energy conversion
- Direct flights
- Direct injection
- Direct integration
- Direct laser writing
- Direct limit
- Direct linear transformation
- Direct manipulation
- Direct message
- Direct methods
- Direct pathway
- Direct photons
- Direct product
- Direct proof
- Direct reduction
- Direct shear test
- Direct stiffness method
- Direct sum
- Direct thrombin inhibitors
- Direct torque control
- Direct-conversion receiver
- Direct-coupled amplifier
- Direct-current plasma
- Direct-drive
- Direct-drive mechanism
- DirectShow
- Directed evolution
- Directed graph
- Directed set
- Directing groups
- Direction cosines
- Direction finding
- Direction of arrival
- Directional antenna
- Directional couplers
- Directional derivative
- Directional drilling
- Directional freezing
- Directional solidification
- Directional stability
- Directional statistics
- Directionality
- Directivity
- Directory
- Directory Access Protocol
- Directory structure
- Directrix
- Dirichlet Integral
- Dirichlet boundary condition
- Dirichlet distribution
- Dirichlet eigenvalue
- Dirichlet problem
- Dirichlet processes
- Dirty data
- Disaccharides
- Disarticulation
- Disassembler
- Disaster recovery
- Disaster recovery plan
- Disc cutter
- Disc filter
- Disc protrusion
- Discectomy
- Discharge
- Discharge coefficient
- Discharge pressure
- Discharge printing
- Disclinations
- Discography
- Discoid lupus erythematosus
- Disconnector
- Discontinuity
- Discontinuity layout optimization
- Discontinuous deformation analysis
- Discounting
- Discoverability
- Discovery Studio
- Discovery of graphene
- Discrete Morse theory
- Discrete Ordinates Method
- Discrete category
- Discrete choice
- Discrete differential geometry
- Discrete dipole approximation
- Discrete element method
- Discrete event dynamic system
- Discrete event simulation
- Discrete group
- Discrete logarithm
- Discrete manufacturing
- Discrete modelling
- Discrete optimization
- Discrete symmetry
- Discrete topology
- Discrete uniform distribution