The clavichord is a stringed rectangular keyboard instrument that was used largely in the Late Middle Ages, through the Renaissance, Baroque and Classical eras.
Historically, it was mostly used as a practice instrument and as an aid to composition, not being loud enough for larger performances. The clavichord produces sound by striking brass or iron strings with small metal blades called tangents. Vibrations are transmitted through the bridge(s) to the soundboard.
1977 unfretted clavichord by Keith Hill
The "Lépante" fretted clavichord, Musée de la Musique, Paris
Tangents
Detail of the Clavichord at Museu de la Música de Barcelona
A keyboard instrument is a musical instrument played using a keyboard, a row of levers that are pressed by the fingers. The most common of these are the piano, organ, and various electronic keyboards, including synthesizers and digital pianos. Other keyboard instruments include celestas, which are struck idiophones operated by a keyboard, and carillons, which are usually housed in bell towers or belfries of churches or municipal buildings.
The piano, a common keyboard instrument
Hammond organ with part of a Leslie speaker shown
Bandoneon
Image: Mosaic of the Female Musicians