Stellar groups are collections of stars that are bound together by gravity. These groups can vary in size and structure, with the most common types being star clusters and galaxies. Star clusters are smaller groups of stars that can be further classified into open clusters, which contain young stars, and globular clusters, which are older and denser. Galaxies, on the other hand, are vast systems that can contain billions of stars, along with gas, dust, and dark matter. The Milky Way is an example of a galaxy that houses our solar system. Understanding stellar groups helps astronomers learn about the formation and evolution of the universe.