A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

D galaxy
dacite
Dactyl
Daedalus, Project
daguerreotype
Daimler, Gottlieb (1834–1900)
Dale, Henry Hallet (1875–1968)
D'Alembert's principle
Dalton, John (1766–1844)
Dalton's law of partial pressures
Dam, Carl Peter Henrik (1895–1976)
Damblanc, Louis (1889–1969)
Damocloid family
damping
Dandelin spheres
Daphnis
Darby family
dark adaptation
dark energy
dark galaxy
dark halo
dark halo crater
dark matter
dark nebula
Darwin, Charles Robert (1809–1892)
Darwin, Erasmus (1731–1802)
datolite
Davida (asteroid)
Davis, Ray(mond) Jr. (1914–2006)
Davisson, Clinton Joseph (1881–1958)
Davisson and Germer experiment
Davy, Humphry (1778–1829)
Dawes' limit
dawn
Dawn (asteroid mission)
dawn rocket
day
Day the Earth Stood Still, The
Daylight Comet of 1910
daylight stream
DC circuits
de Broglie and matter waves
de Concilio, Januarius (1836–1898)
de Duve, Christian (1917–2013)
de Forest, Lee (1873–1961)
de LaTour, Cagniard (1777–1859)
de Laval, Gustav (1845–1913)
de Laval nozzle
de L'Hôpital, Guillaume François Antoine, Marquis de (1661–1704)
de Malve's theorem
de Méré's problem
de Moivre, Abraham (1667–1754)
de Moivre's theorem
De Morgan, Augustus (1806–1871)
de Sitter, Willem (1872–1934)
de Sitter model
de Vaucouleurs, Gérard Henri (1918–1995)
de Vries, Hugo (1848–1935)
deafness
deamination
DeBakey, Michael Ellis (1908–2008)
debris avalanche
Debus, Kurt H. (1908–1983)
Debye, Peter Joseph Wilhelm (1884–1966)
decagon
decapod
decay constant
decibel (unit)
deciduous tree
decimal
decimal fraction
decimal system
Declaration of Principles (... Following Detection of ETI)
declination
decomposition, chemical
decompression chamber
decongestant
Dee, John (1527–1609)
deep fascia
Deep Impact
deep sky object
deep space
Deep Space 1
Deep Space 2
Deep Space Communications Complex
Deep Space Network
Deep Space Station
deep vein thrombosis
deflector shield
Defoe, Daniel (1660–1731)
DeFrance, Smith J. (1896–1985)
degaussing
degenerate matter
degree
degree of freedom
dehydration
Deimos
Deinococcus radiodurans
deism
del
Delaporte, Eugène Joseph (1882–1955)
Delbrück, Max (1906–1981)
deletion
deliquescence
delirium
delocalization
Delphinus (constellation)
delta (river)
Delta (rocket)
Delta IV Heavy
Delta Cephei
Delta Cephei star
delta curve
delta rays
Delta Scuti star
delta V
deltahedron
deltoid
deltoid muscle
deluge collection pond
Dembowska (asteroid)
dementia
demineralization
Democritus of Abdera (c. 470–400 BC)
demography
Demosat (Demonstration Satellite)
denaturation
dendrite
Deneb (Alpha Cygni)
Deneb Kaitos (Beta Ceti)
Denebola (Beta Leonis)
dengue fever
denominator
Denpa
densitometer
density
density parameter
density wave
dental nerve
dentition
denudation
deoxyribonucleic acid (DNA)
deoxyribose
deposition
depression (medical condition)
depression (meteorology)
depth of field
depth perception
Derham, William (1657–1735)
derivative
derived unit
dermatitis
dermis
Desargues, Girard (1591–1661)
Descartes, Rene (1596–1650)
descending node
descriptive geometry
Desdemona
desert
desert birds and mammals
desert life
desiccant
desiccator
Despina
Destination Moon
Destiny Laboratory
destructive margin
Desulfotomaculum
detonator
detection of life
detergent
determinant
determinism
deterministic system
deuterium
DEVELOPMENTAL BIOLOGY AND EMBRYOLOGY
Devil's curve
Devonian period
Dewar, James (1842–1923)
Dewar flask
Dewdney, Alexander Keewatin (1941–)
Dewey, John (1859–1952)
dextrin
diabetes insipidus
diabetes mellitus
diabetic heart disease
diabetic neuropathy
diabetic retinopathy
diagenesis
diagonal (geometry)
diagonal (telescope)
dialysis
diamagnetism
Diamant
diameter
diametric drive
diamond
diamond ring effect
diapause
diaphragm
diarrhea
diastase
diatom
diazepam
diazonium compound
dicarboxylic acid
dice
dichroism
Dicke, Robert Henry (1916–1997)
dicotyledon
Diderot, Denis (1713–1784)
dielectric
dielectric constant
Diels, Otto Paul Hermann (1876–1954)
Diels-Alder reaction
Diesel, Rudolf (1858–1913)
diesel engine
diffeomorphism
difference equation
differential geometry
differential rotation
differential sail
differentiation
diffraction
diffraction grating
diffuse interstellar bands
diffuse nebula
diffusion
digestion
digestive system
Digges, Leonard (c. 1520–c. 1559) and Thomas (c. 1545–1595)
digit
digital root
digitalis
digitoxin
digoxin
dike
dimension
dimensional analysis
dinoflagellate
dinosaur
dinosaurs, intelligent
diode
diode sail
diogenite
diol
Dione
Diophantine equation
Diophantus of Alexandria (AD c. 200–c. 284)
diopter
diorite
dip circle
diphtheria
diploblastic
diplococcus
diploid
dipole
Diptera
Dirac, Paul Adrien Maurice (1902–1984)
direct (rotation)
direct ascent
directed graph
directed panspermia
direction finder
directrix
Dirichlet, Peter Gustav Lejeune (1805–1859)
disaccharide
discharge tube
discordant redshift
Discovery (Shuttle Orbiter)
Discovery Program
discriminant
discus fish
disease
disinfectant
disjunction drive
disk (mathematics)
disk (astronomy)
disk, galactic
disk galaxy
disk star
dislocation
Disney, Walt (1901–1966)
dispersion
displacement
displacement current
disproportionation
dissection
disseminated intravascular coagulation
dissipative structure
dissociation
distal
distillation
distortion
distortion illusion
distributive
diuretic
diurnal
div
divergence
diving, deep-sea
division
DLR (Deutschen Zentrum für Luft und Raumfahrt)
DME (Direct Measurement Explorer)
DMSP (Defense Meteorological Satellite Program)
DNA (deoxyribonucleic acid)
DNA replication
DNA sequencing
Dnepr
Dobrovolsky, Georgy Timofeyevich (1928–1971)
Dobsonian telescope
Dobzhansky, Theodosius (1900–1975)
dock
docking (spacecraft)
dodecahedron
DODGE (Department Of Defense Gravity Experiment)
doldrums
dolerite
Dollfus, Audouin Charles (1924–2010)
Dollond, John (1706–1761)
dolomite
dolphins, as a form of alien intelligence
domain (biology)
domain (mathematics)
dominant
Dominian Astrophysical Observatory
domino
domino problem
Donati, Giovanni Battista (1826–1873)
Doolittle, James Harold (1896–1993)
"Doomsday" asteroid
doomsday machine
dopamine
dopant
Doppler boosting
Doppler effect
Doppler tracking
Dorado (constellation)
dormancy
Dornberger, Walter (1895–1980)
Dornier, Claude (1884–1969)
dorsal
dosimeter
Double Cluster (h and Chi Persei; NGC 869 and NGC 884)
double planet
Double Quasar
double radio source
double refraction
double-mode variable
doublet
Douglas Skyrocket
Douglass, Andrew Ellicott (1867–1962)
Down's syndrome
dowsing
dowsing and a possible magnetic sense
Doyle, Arthur Conan (1859–1930)
DQ Herculis star
Draco (constellation)
Draco Dwarf
drag
Dragon (spacecraft)
Dragon's Egg
Drake, Frank Donald (1930–2022)
Drake equation
Drake's cryptogram
Draper, Charles Stark (1901–1987)
Draper, Henry (1837–1882)
Draper, John William (1811–1882)
Dream Chaser
dreams
Drew, Charles Richard (1905–1950)
Dreyer, John Louis Emil (1852–1926)
drift
drone
Drosophila
drought
DRTS (Data Relay Test Satellite)
drug
drumlin
drupe
dry cell
dry cleaning
Dry Valleys, Antarctica
Dryden, Hugh Latimer (1898–1965)
DS4G (dual-stage 4-grid) ion engine
Dryden Flight Research Center
Dschubba (Delta Scorpii)
DSCS (Defense Satellite Communications System)
D-type asteroid
du Prel, Carl (1839–1899)
dual
dualism
Dubhe (Alpha Ursae Majoris)
dubnium
duck-billed platypus
ductility
Dudeney, Henry Ernest (1857–1930)
Duke, Charles Moss, Jr. (1935–)
Dulong, Pierre Louis (1785-1838)
Dulong and Petit's law
Dumas, Jean Baptiste André (1800–1884)
Dumbbell Nebula (M27, NGC 6853)
dumortierite
dune
Dunham, Theodore (1897–1984)
dunite
Dunlop, James (1793–1848)
Dunlop, John Boyd (1840–1921)
Dunn, Louis G. (1908–1979)
Dunning, John Ray (1907–1975)
Dunsany, Lord (1878–1957)
duodecimal
duodenum
Dupin cyclide
duplicating the cube
duplication
dura mater
duralumin
Durant III, Frederick Clark (1916–2015)
Dürer, Albrecht (1471–1528)
Dürer's shell curve
dust
dwarf bacteria
dwarf elliptical galaxy
dwarf galaxy
dwarf irregular galaxy
dwarf molecular cloud
dwarf planet
dwarf spheroidal galaxy
dwarf star
Dwingeloo 1
DX Cancri
dye
dynamic pressure
dynamical method
dynamical system
dynamical time
dynamics
Dynamics Explorer
dynamite
dynamometer
Dyna-Soar
dyne
dysbarism
dysentery
Dyson, Frank Watson (1868–1939)
Dyson, Freeman John (1923–2020)
Dyson slingshot
Dyson sphere
dysprosium