HARPSICHORD, a musical instrument in which the sounds are produced by stretched wires. The spinet and virginals, &c., preceded the harpsichord, which was an improvement on them; and all of these were derived from the harp. Each was really a horizontal harp enclosed in a sonorous case; the wires being struck by jacks moved by finger-keys. In the beginning of the eighteenth century the pianoforte was invented as an improvement upon the harpsichord. Instead of the jacks armed with crowquills which struck the harpsichord wires, hammers covered with prepared leather were used in the pianoforte. Mason, the English poet and amateur musician, introduced great improvements in the mechanism of the keys and hammers. Clementi, Broadwood, and other makers in London, have, since then, so greatly improved the pianoforte as to justify its being considered, in its latest form, almost an English instrument. See PIANOFORTE.