It is the distance you move the mouse across the pad to turn your character once around. It combines sens, DPI and how far the game turns per mouse count, so it is comparable between games.
Under 25 cm counts as fast (a lot of wrist), 25 to 45 cm as balanced, over 45 cm as calm (a lot of arm). Most well-known players sit roughly between 40 and 70 cm (estimate from ProSettings.net, 2026).