The cythara is a wide group of stringed instruments of medieval and Renaissance Europe, including not only the lyre and harp but also necked, string instruments. In fact, unless a medieval document gives an indication that it meant a necked instrument, then it likely was referring to a lyre. It was also spelled cithara or kithara and was Latin for the Greek lyre. However, lacking names for some stringed instruments from the medieval period, these have been referred to as fiddles and citharas/cytharas, both by medieval people and by modern researchers. The instruments are important as being ancestors to or influential in the development of a wide variety of European instruments, including fiddles, vielles, violas, citoles and guitars. Although not proven to be completely separate from the line of lute-family instruments that dominated Europe, arguments have been made that they represent a European-based tradition of instrument building, which was for a time separate from the lute-family instruments.

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.