Lewis & Short

mŏnŏchordos, on, adj., = μονόχορδος, of one string: cithara, Aeron. ad Hor. A. P. 216.
Subst.: mŏnŏchordon, i, n., μονόχορδον, the monochord, tonometer, Boëth. Instr. Mus. 1, 27 al.‡ † mŏnŏchŏrĭus, ii, m., = μόνοσ-χόρος, one who dances alone, who executes a pas seul, Not. Tir. p. 173.