> The Elo rating system is a method for calculating the relative skill levels of players in zero-sum games such as chess. It is named after its creator Arpad Elo, a Hungarian-American physics professor.
There are other rating systems that are similar, but people commonly call any similar rating system "Elo". In this case, Lichess uses https://en.m.wikipedia.org/wiki/Glicko_rating_system, so the GP is arguing against calling it "Elo". I think it's kind of a pedantic point given that more people will understand "Elo" than "glicko-2", but I suppose "rating" would be clearer than either term.
