Nidan, the Japanese term for "second dan", refers to the second degree black belt in martial arts. Synonyms for nidan include "second degree", "second dan", "level two black belt", and "intermediate black belt". In Japanese martial arts like karate, judo, and aikido, the attainment of nidan requires several years of grueling training, discipline, and mastery of techniques. Other terms that are associated with nidan in martial arts include strong, skilled, experienced, dedicated, and disciplined. Achieving nidan signifies a significant milestone for martial artists and underscores their dedication to the art, as well as demonstrates their ability to teach others and guide them along the path to mastery.