D
- Dark Burst
- Dark Energy
- Dark Halo
- Dark Matter
- Dark Nebula
- Day
- Deceleration Parameter
- Declination
- Degenerate Electron Pressure
- Degree (angular)
- Degree (temperature)
- Density
- Density Parameter
- Density Wave Model
- Descending Node
- Destructive Interference
- Differential Rotation
- Differentiated Object
- Disk Galaxies
- Displacement
- Dissociation
- Distance
- Distance Modulus
- Disturbed Galaxies
- Diurnal Motion
- Doppler Shift
- Dust Grain
- Dwarf Galaxy
- Dwarf Novae
- Dynamical Friction