Clavicitherium

[T]he harpſichord is an improvement of the Clavicitherium, an inſtrument known in England in Gower's time by the name of the Citole, from Cistella, a little cheſt.

The writer referred to [Edward Francis Rimbault] traces the instrument from the ancient lyre, through various mechanical phases, the harp, psaltery, dulcimer, etc. to the clavicitherium—a name compounded from the Latin clavis, a key, and cithera, the name of an ancient instrument of music, which consisted of strings drawn over a sounding wooden surface or bottom, and not unlike the modern guitar. The clavicitherium was an oblong box, containing a number of strings arranged in a triangular form, and which were struck by a plectrum—a little mallet, commonly made of ivory, with which the ancients beat the strings of the lyre.