Source : Webster's Revised Unabridged Dictionary (1913)

Decachord \Dec"a*chord\, Decachordon \Dec`a*chor"don\, n. [Gr.
   deka`chordos tenstringed; de`ka ten + chordj` a string.]
   1. An ancient Greek musical instrument of ten strings,
      resembling the harp.

   2. Something consisting of ten parts. --W. Watson.