| Term | Definition / Meaning / Stand for |
| DLA |
Damped Lyman Alpha (Systems) |
| DLA |
Damped Lyman-Alpha system |
| DBL |
Dark Banding Layer (On Gas Giants) |
| DCS |
Dark Cosmic Survey |
| DE |
Dark Energy |
| DGS |
Dark Galaxy Survey |
| DLW |
Dark Lunar Wavelength (Spectral Analysis) |
| DME |
Dark Matter Emission |
| DMF |
Dark Matter Fraction |
| DF |
Dark Matter Free (Galaxy Type) |
| DAMPE |
Dark Matter Particle Explorer |
| DMS |
Dark Matter Survey |
| DST |
Dark Sky Telescope |
| DSSP |
Dark Star Surface Potential |
| DST |
Dark Star Theorem |
| DUNE |
Dark Universe Explorer |
| DWM |
Dark World Mapping (Planetary Exploration) |
| DAI |
Data Acquisition Interface |
| DAP |
Data Analysis Pipeline |
| DAC |
Data Archive Center |
| DMT |
Data Management Tool |
| DOR |
Data Output Rate |
| DR |
Data Release |
| DSTP |
Data System Test Program |
| DTA |
Data Telemetry Array |
| DACE |
Data and Analysis Center for Exoplanets |
| DECIGO |
Deci-hertz Interferometer Gravitational Wave Observatory |
| DRA |
Declination-Right Ascension Coordinate System |
| D |
Declination |
| DAVINCI |
Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging |
| DGC |
Deep Galactic Core |
| DENIS |
Deep Near Infrared Survey |
| DNR |
Deep Near-Infrared (Astronomy) |
| DNC |
Deep Nulling Coronagraphy (Exoplanet Detection) |
| DPS |
Deep Photometric Survey |
| DRE |
Deep Radio Experiment |
| DSO |
Deep Sky Object |
| DSA |
Deep Space Antenna |
| DSCOVR |
Deep Space Climate Observatory |
| DSG |
Deep Space Gateway |
| DWF |
Deep Wide Field |
| DWF |
Deep Wide-Field (Survey) |
| DMS |
Degrees, Minutes, Seconds (Coordinate Format) |
| DTD |
Delay-Time Distribution (Supernova Studies) |
| DCEP |
Delta Cephei, a class of Cepheid variable stars |
| DSCT |
Delta Scuti, a class of pulsating variable stars |
| DISR |
Descent Imager/Spectral Radiometer |
| DEMETER |
Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions |
| DGLR |
Deutsche Gesellschaft fur Luft- und Raumfahrt (German Society for Aeronautics and Astronautics) |
| DLR |
Deutsches Zentrum fur Luft- und Raumfahrt (German Aerospace Center) |
| DARM |
Differential Arm (Gravitational Waves) |
| DCR |
Differential Chromatic Refraction |
| DFA |
Differential Flux Analysis |
| DGC |
Differential Gravitational Constant |
| DPP |
Differential Planetary Precession |
| DSC |
Differential Stellar Count |
| DVG |
Differential Velocity Gradient (Stellar Studies) |
| DIA |
Diffraction Imaging Array |
| DLT |
Diffraction Limited Telescope |
| DAP |
Diffuse Astrophysical Plasma |
| DCS |
Diffuse Cosmic Structure |
| DGL |
Diffuse Galactic Light |
| DIBRE |
Diffuse Infrared Background Experiment |
| DLW |
Diffuse Lunar Water (Study of Moon's Hydration) |
| DNP |
Diffuse Nebular Plasma |
| DSF |
Diffuse Star Formation (In Galaxies) |
| DXL |
Diffuse X-ray emission from the Local galaxy |
| DIBS |
Diffuse |
| DASCH |
Digital Access to a Sky Century at Harvard |
| DWARF |
Digitally Weighted Aperture Radiation Framework |