D Mesons --- Darboux Transformations --- Dark Haloes -- Dark Matter --- Data --- De Sitter Space --- Deceleration Parameter --- Decoherence; --- Decohering Histories -- Deconfinement Phase Transition --- Deep Exclusive Scattering --- Deep Inelastic Scattering --- Deep Learning --- Defects --- Deformed Special Relativity --- De Haas-Einstein Effect --- Delta Function --- Delta Scuti Stars --- Density Functionals --- Density of Universe --- Detectors --- Determinants --- Determinism --- Deuterium --- Deuterons --- Diamond Anvil Cells --- Dielectrics --- Difference Equations --- Differential Equations --- Differential Forms --- Differential Geometry --- Diffraction (High Energy Physics) --- Diffuse Interstellar Bands --- Diffuse Interstellar Clouds --- Diffusion --- Diffusion Equation --- Dilatons --- Dileptons --- Diodes --- Diophantine Equations --- Diquarks --- Dirac Delta Function --- Dirac Equation --- Dirty Fireballs --- Discharges (Electric) --- Discrete Mathematics --- Dislocations --- Disordered Alloys --- Disordered Systems --- Disoriented Chiral Condensate --- Dispersion Relations --- Dissipative Systems --- Distance Candles --- Distribution Theory --- Division Algebras --- Domain Walls --- Donaldson Theory --- Doppler Effect --- Doubly Special Relativity --- Down Quark --- Dualities in Field Theory --- Duality in Differential Geometry --- Dunkl Operators --- Dust --- Dust Clouds -- Dwarf Galaxies --- Dwarf Novae --- Dynamical Triangulation --- Dynamics --- Dynamos --- Dyson-Schwinger Equation