The kithara or cithara was an ancient Greek musical instrument in the lyre or lyra family. In modern Greek the word kithara has come to mean "guitar", a word which etymologically stems from kithara.
The kithara was a professional version of the two-stringed lyre. As opposed to the simpler lyre, which was a folk-instrument, the kithara was primarily used by professional musicians, called kitharodes. The kithara's origins are likely Anatolian. The barbiton was a bass version of the kithara popular in the eastern Aegean and ancient Anatolia.
In the Middle Ages, cythara was also used generically for stringed instruments including lyres, but also including lute-like instruments. The use of the name throughout the Middle Ages looked back to the original Greek kithara, and its abilities to sway people's emotions.