Which term refers to a second Dan black belt?

The correct term for a second Dan black belt is "Kyo Sa Nim." This title is commonly used within martial arts, particularly in taekwondo, to signify that the practitioner has reached the level of instructor certified to teach students. In many martial arts organizations, practitioners progress through ranks, and the title "Kyo Sa Nim" denotes that a person has achieved a level of proficiency and understanding of the martial art that qualifies them to instruct others.

The other terms have different meanings in the context of martial arts. "Jo Kyo Nim" generally refers to an instructor at the first level, while "Kwan Chang Nim" is a title typically reserved for the founder or head of a school or organization. "Sabum-Nim" is used for a master instructor, often at the level of sixth Dan or higher. Understanding these distinctions helps clarify the hierarchy and the meaning of various titles used in martial arts training and instruction.