The disk galaxy NGC 5866,
seen nearly edge-on.
Credit: NASA, ESA, and The Hubble Heritage Team STScI/AURA.
A disk galaxy is a galaxy with a prominent wide, thin disk
of stars. This description applies to spiral
galaxies (including barred spirals)
and lenticular galaxies, but not
to elliptical galaxies, dwarf spheroidals, and some peculiar galaxies.