Vulcan lute
From Memory Alpha, the free Star Trek reference.
The Vulcan lute (sometimes referred to as Vulcan harp, Vulcan lyre, or lytherette) is a five-stringed instrument, played on the planet Vulcan, that is tuned on a diatonic scale and noted to be very soothing. (VOY: "Innocence")
Spock was proficient at playing the Vulcan lute and was known to play it often during his off-duty hours. (TOS: "Charlie X", "The Conscience of the King", "Amok Time", "The Way to Eden"; Star Trek V: The Final Frontier)
Tuvok was also a proficient Vulcan lute player. He would often play his lute while reciting Falor's Journey to his youngest son. (VOY: "Persistence of Vision", "Innocence", "Riddles")
Melian, an Aldean musician also owned a Vulcan lute. (TNG: "When The Bough Breaks").
One of Intendant Kira Nerys' Vulcan eunuchs played a Vulcan harp for her while a second eunuch gave her a massage. (DS9: "Through the Looking Glass")
[edit] Background
The Vulcan lute seen in "Charlie X" was designed by Wah Chang.
The Vulcan lute has been described as a five-stringed instrument tuned in a diatonic scale in "Innocence", but is seen to have twelve strings. It is strongly suggested that the lute is instead tuned in a twelve-tone chromatic scale, since a seven-tone diatonic scale can fit in neither 5 nor 12 strings.
In a deleted scene from "Elaan of Troyius", Spock revealed that he took second place in the All-Vulcan Music Competition, and that his father had taken first place.
