Disk (the outer regions of the disk is where our Sun and Solar System lie)
(Nuclear) Bulge, Halo, and (Galactic) Nucleus
And scattered in the Halo around our galaxy are enormous clusters of hundreds of
thousands of stars, called Globular Clusters.
Further scattered about our galaxy, mostly in the disk and spiral arms, are open star
clusters and nebulae. Each star in our galaxy is an enormous ball of gas, made up mostly of hydrogen.