The Collaborative International Dictionary of English v.0.48:

Manichord \Man"i*chord\, Manichordon \Man`i*chor"don\, [L.
   monochordon, Gr. ?; -- so called because it orig. had only
   one string. See Monochord.] (Mus.)
   The clavichord or clarichord; -- called also dumb spinet.
   [1913 Webster]