The belt system in Jiu Jitsu stands for a professional's ability level
https://www.scribd.com/document/846419661/Your-Overview-to-Gracie-Barra-Jiu-Jitsu-in-Phoenix-Metro-Courses-and-Neighborhood-137980
The belt system in Jiu Jitsu represents a practitioner's skill degree, with each color indicating development from newbie to progressed