clavichord, keyboard musical instrument invented in the Middle Ages. It consists of a small rectangular wooden box, placed upon a table or on legs, containing a sounding board and a set of strings. Keys cause the strings to be struck with small wedges of metal called tangents, which not only set the string into vibration but determine its vibrating length by means of a sort of fretting. Thus one string suffices for about four keys. Early in the 18th cent., clavichords were built with a string for each key; such instruments were more expensive and harder to tune, but gradually supplanted the older ones. The clavichord was musically important from the 16th until the end of the 18th cent. when the pianoforte replaced it. The most notable composer to write expressly for it was Carl Philipp Emanuel Bach.

Early keyboard instrument, an important forerunner of the piano. It flourished circa 1400–1800, especially in Germany. It is usually rectangular, with the keyboard inset. The strings are struck by metal tangents, rather than plucked as on the harpsichord. The tangent becomes the endpoint of the vibrating string; thus the point where it strikes determines the pitch. So-called fretted clavichords permit more than one tangent to strike a single pair of strings (which somewhat limits the notes that can be sounded simultaneously); unfretted clavichords use only one tangent per pair of strings. The player's touch can produce dynamic variation; variation in finger pressure can even produce vibrato. Its tone is silvery and soft, best suited for intimate music.

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