disk galaxy

disk galaxy, NGC 5866

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.