Galaxies are large groups of gravitation-bound stars. Our Sun in in a galaxy called the Milky Way.
There are several types of common galaxies. Spiral galaxies have star arranged in spiral arms. Stars the the arms tend to be newer stars. The Milky Way is a spiral galaxy.Elliptical galaxies are arranged in oval bulges. They are more compact than spiral galaxies and tend to contain older, redder stars. Finally, there are irregular galaxies in many different forms.