A "Galactic Arm" refers to a major region of stars, gas, and dust within a galaxy, particularly in spiral galaxies like the Milky Way. These arms are sites of active star formation and contain many young, bright stars, as well as nebulae and other celestial objects. In the Milky Way, there are several prominent arms, including the Orion Arm, where our solar system is located. The arms are not solid structures but rather regions where stars are more densely packed, creating a spiral pattern that can be observed from a distance.