Zither

or Cithern, a stringed musical instrument. In medieval times it was a modified form of the lute or guitar, and like a guitar was held vertically. The modern zither is more like a four-sided harp. It is laid horizontally on a table. There are thirty to forty metal strings which are played or twanged with a plectum of ivory or horn. The length of the strings is varied by stopping on a fret-board.