- A small, dim galaxy, intermediate in size between a regular galaxy and a globular cluster. Like larger galaxies, dwarf galaxies are classified as elliptical, spiral, or irregular based on their shape. The closest known galaxy to the Milky Way is a dwarf galaxy in Canis Major that is believed to be losing stars to ours. Many astronomers think that most of the large galaxies seen today were formed either by collisions of dwarf galaxies, which formed first in the aftermath of the Big Bang, or by larger galaxies attracting material away from dwarf galaxies.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.