A rating system can be any kind of rating applied to a certain application domain. They are often created using a rating scale.
Examples include:
Motion picture content rating system Motion Picture Association film rating system Canadian motion picture rating system Television content rating system Video game content rating system DC Comics rating system Marvel Comics rating system Elo rating system Glicko rating system Chess rating system Rating system of the Royal Navy Star rating Sports rating system Wine rating Texas Education Agency accountability ratings system Global Rating System is a term used by Fitch Moodys S&P Global Eco Home Global Sustainability Assessment System International Sustainability Rating System Forbes Travel Guide Hotels Digest COSMIN OSCE CISA ITU GCI IMF Statista Vertiv