The term 'DULCIMER's Kin' refers to three stringed instruments: the HARP (4 letters), ZITHER (6 letters), and PSALTERY (8 letters). The HARP is a multi-stringed instrument that has been around for centuries, and is often used in classical music. The ZITHER is a plucked string instrument with a flat soundboard, and is popular in folk music. The PSALTERY is a box-shaped instrument with strings stretched across it, and is often used in religious music. All three of these instruments are related to the DULCIMER, and are commonly used in various genres of music.