College and university rankings are lists that rank schools based on different aspects that they looked at. To rank the schools, the people who make the list look at things like student test scores, the school's prestige (which is how well-known the school is), how many students get jobs after they graduate from that school, how much money the students make after they graduate, and the resources (like classrooms and faculty) that the school has to offer. Someone could look at the rankings to see which schools are the best in different areas, like job prospects or prestige.