Galaxies are generally grouped by their appearance into three types: spiral, elliptical, and irregular. These groups are further subdivided into categories like barred spiral and grand design spiral, giant elliptical and dwarf spheroidal, and Magellanic irregular or peculiar. Galaxies are also often categorized by characteristics other than their appearance. For example, there are starburst galaxies, merging galaxies, active galaxies, radio galaxies, and many more.