The Collaborative International Dictionary
dumb spinet
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.
Wiktionary
dumb spinet
n. clavichord