The cithara or kithara (Greek: κιθάρα, kithāra, Latin: 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 whose origins are found in 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 Asiatic. The barbiton was a bass version of the kithara popular in the eastern Aegean and ancient Asia Minor.
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 cithara and its abilities to sway people's emotions.
The kithara had a deep, wooden sounding box composed of two resonating tables, either flat or slightly arched, connected by ribs or sides of equal width. At the top, its strings were knotted around the crossbar or yoke (zugon) or to rings threaded over the bar, or wound around pegs. The other end of the strings was secured to a tail-piece after passing over a flat bridge, or the tail-piece and bridge were combined. Most vase paintings show kitharas with seven strings, in agreement with ancient authors, but these also mention that occasionally a skillful kitharode would use more than the conventional seven strings.
It was played with a rigid plectrum held in the right hand, with elbow outstretched and palm bent inwards, while the strings with undesired notes were damped with the straightened fingers of the left hand.