Abell cluster
active galactic nucleus
Ambartsumian's Knot
Andromeda Galaxy (M31, NGC 224)
ansa
Antennae (NGC 4038 and NGC 4039)
Antlia Dwarf Galaxy
Aquarius Dwarf
Atoms for Peace Galaxy (NGC 7252)

Barnard's Galaxy (NGC 6822)
barred spiral
Bautz-Morgan classification
BL Lacertae object
Black Eye Galaxy (M64, NGC 4826)
blazar
blue compact dwarf galaxy
Box, The (Hickson 61)
Butcher-Oemler effect
BX 442

Canes Venatici Cloud
Canes Venatici I Group
Canes Venatici II Group
Canis Major Dwarf
Carina Dwarf
Cartwheel Galaxy (ESO350-40)
Cassiopeia Dwarf (Cas dSph)
Centaurus A (NGC 5128)
Centaurus Cluster
Circinus Galaxy
Cloverleaf Quasar (H1413+117)
cluster of galaxies
Coddington's Nebula (IC 2574)
Coma Cluster
Copeland's Septet (Hickson 57)
Cygnus A (3C 405)

D galaxy
dark galaxy
dark halo
density wave
differential rotation
discordant redshift
disk galaxy
Doppler boosting
Double Quasar
Draco Dwarf
dwarf elliptical galaxy
dwarf irregular galaxy
dwarf spheroidal galaxy
dwarf galaxy
Dwingeloo 1

Einstein Cross
elliptical galaxy
entrainment
Ep galaxy
Eyes, The (NGC 4435 and 4438)

Faber-Jackson relation
Fanaroff-Riley classification
Fornax A (NGC 1316)
Fornax Cluster
Fornax Dwarf

galactic bulge
galactic center
galactic coordinates
galactic disk
galactic halo
galactic magnetic field
galactic noise
galactic rotation
galaxy
Galaxy, the
galaxy classification
galaxy formation
galaxy interaction
Great Annihilator
Great Attractor
Great Wall
Grus Quartet

Haro galaxy
head-tail galaxy
Helix Galaxy (NGC 2685)
Hercules Cluster (Abell 2151)
Hoag's Object (PGC 54559)
Hockey Stick (NGC 4656)
Holmberg II Dwarf Irregular Galaxy
hot spot

IC 10
infrared galaxy
Integral Sign Galaxy (UGC 3697)
intergalactic medium
intracluster medium
irregular galaxy

jet

Keenan's System (NGC 5216 and NGC 5218)

Laing-Garrington effect
Large Magellanic Cloud
lenticular galaxy
Leo I
Leo II
Leo III
Lindsay-Shapley Ring (AM0644-741)
LINER (low-ionization nuclear emission-line region)
Local Group
Local Supercluster
low surface brightness galaxy

M32 (NGC 221)
M74 (NGC 628)
M81 (NGC 3031)
M82 (NGC 3034)
M87 (NGC 4486)
M89 (NGC 4552)
M94 (NGC 4736)
M95 (NGC 3351)
M101 (NGC 5457)
M110 (NGC 205)
MACHO (Massive Astronomical Compact Halo Object)
Maffei 1 Group
Magellanic Clouds
Malin-1
Malmquist effect
Markarian's Chain
mass-luminosity ratio
Mice, The (NGC 4676 A and B)
Milky Way
Minkowski's Object (Arp 133)
Mirach's Ghost (NGC 404)

N galaxy
Needle Galaxy
NGC 1187
NGC 253
NGC 4565
NGC 4622
NGC 5128 Group
NGC 891

odd radio circle

Orion Arm

peculiar galaxy
Pegasus Dwarf Spheroidal (Peg dSph)
Perseus Arm
Perseus Cluster (Abell 426)
Perseus-Pisces Supercluster
Phoenix Cluster
Phoenix Dwarf
Pisces Cloud (NGC 379, 380, 382-5)
Pisces Dwarf (LGS-3)
polar ring galaxy
Polarissima Borealis (NGC 3172)

quasar

radio galaxy
relativistic beaming
ring galaxy
Robert's Quartet
rotation curve

Sagittarius Arm
Sagittarius Dwarf Elliptical Galaxy (Sag dSph)
Sagittarius Dwarf Irregular Galaxy (Sag dIrr)
satellite galaxy
Sculptor Dwarf
Sculptor Group
Sextans Dwarf
Seyfert galaxy
Seyfert's Sextet (Hickson 79)
Shapley Concentration
shell galaxy
Small Magellanic Cloud
Sombrero Galaxy (M104, NGC 4594)
Spindle Galaxy (NGC 3115 and NGC 5866)
spiral galaxy
starburst galaxy
Stephan's Quintet
Sunflower Galaxy (M63, NGC 5055)
supercluster
supergalactic plane
superluminal radio source
supermassive black hole

Tadpole Galaxy
tidal dwarf galaxy
tidal tail
Triangulum Galaxy (M33, NGC 598)
Tully-Fisher relation

ultra-luminous infrared galaxy (ULIRG)
Ursa Minor Dwarf

Virgo Cluster

Whirlpool Galaxy (M51, NGC 5194)
Willman 1
Wolf-Lundmark-Melotte Galaxy (WLM Galaxy)

X-ray cluster