The Collaborative International Dictionary of English v.0.48:

Harpsichord \Harp"si*chord\ (-k[^o]rd), n. [OF. harpechorde, in
   which the harpe is of German origin. See Harp, and
   Chord.] (Mus.)
   A harp-shaped instrument of music set horizontally on legs,
   like the grand piano, with strings of wire, played by the
   fingers, by means of keys provided with quills, instead of
   hammers, for striking the strings. It is now superseded by
   the piano.
   [1913 Webster]

WordNet (r) 3.0 (2006):

harpsichord
    n 1: a clavier with strings that are plucked by plectra mounted
         on pivots [syn: harpsichord, cembalo]

Moby Thesaurus II by Grady Ward, 1.0:

38 Moby Thesaurus words for "harpsichord":
   Klavier, Steinway, baby grand, cembalo, clarichord, clavicembalo,
   clavichord, clavicittern, clavicymbal, clavicytherium, clavier,
   concert grand, cottage piano, couched harp, dulcimer harpsichord,
   grand, grand piano, hammer dulcimer, harmonichord, manichord,
   manichordon, melodion, melopiano, monochord, pair of virginals,
   parlor grand, pianette, pianino, piano, piano-violin, pianoforte,
   sostinente pianoforte, spinet, square piano, upright,
   upright piano, violin piano, virginal