A galaxy was a massive, gravitationally bound assemblage of stars, an interstellar medium of gas and dust, and dark matter. Typical galaxies contained ten million to one trillion (107 to 1012) stars, all orbiting a common center of gravity, usually a supermassive black hole. Galaxies could also contain a large number of star systems and star clusters as well as black holes and various types of nebulae.
Galaxies often orbited one another in galaxy groups. The Local Group was the galaxy group which contained the Milky Way and Andromeda galaxies. The Local Group is part of the Virgo Supercluster, an even larger collection of galaxies. The Virgo Supercluster is likewise part of the enormous Laniakea Supercluster. The Intergalactic Void was the vast, and mostly star-less, space between the galaxies.