The term 'Zither Cousin' is a reference to the HARP, which is a stringed instrument that has been used for centuries. The HARP is a cousin of the zither, which is a type of stringed instrument that is played by plucking the strings with the fingers or a plectrum. Both instruments have a similar construction, but the HARP has a curved neck and a triangular frame, while the zither has a flat neck and a rectangular frame. The HARP is one of the oldest known instruments and has been used in many different cultures throughout history.