Zithers are a class of stringed instruments. Historically, it could be any instrument of the psaltery family. In modern terminology, it is more specifically an instrument consisting of many strings stretched across a thin, flat body, the topic of this article.
Different concert zithers
Plate. The Romance of the Western Chamber. In a scene from a popular play, the heroine is shown in contemplation, playing her zither. From China, Qing Dynasty, 18th century CE. National Museum of Scotland, Edinburgh
Chinese guqin with seven strings
Alpine Scheitholt
The kithara, or Latinized cithara, was an ancient Greek musical instrument in the yoke lutes family. It was a seven-stringed professional version of the lyre, which was regarded as a rustic, or folk instrument, appropriate for teaching music to beginners. As opposed to the simpler lyre, the cithara was primarily used by professional musicians, called kitharodes. In modern Greek, the word kithara has come to mean "guitar", a word which etymologically stems from kithara.
Woman with cithara (right) and sambuca (left). Roman fresco from Pompeii, 1st century CE (National Archaeological Museum, Naples).
Apollo kitharoidos (Apollo holding a cithara and wearing the customary kitharōdos’ robes) and musagetes (leading the Muses). Marble, Roman artwork, 2nd century CE.
Greek vase drawing depicting a man playing a cithara with eight strings. Note the plectrum in his lowered right hand.
Kithara player by the Berlin Painter c. 490 BCE