Galactic interactions refer to the gravitational interactions between galaxies in the universe. These interactions can occur when two galaxies come into close proximity to each other and their gravitational fields affect each other. This can lead to a variety of phenomena, such as galaxy mergers, tidal interactions, and the formation of new stars and structures. Studying galactic interactions can provide insights into the evolution and dynamics of galaxies, as well as the formation and evolution of the large-scale structure of the universe.