The Collaborative International Dictionary of English v.0.48:

Harmonist \Har"mo*nist\ (h[aum]r"m[-o]*n[i^]st), n. [Cf. F.
   harmoniste.]
   1. One who shows the agreement or harmony of corresponding
      passages of different authors, as of the four evangelists.
      [1913 Webster]

   2. (Mus.) One who understands the principles of harmony or is
      skillful in applying them in composition; a musical
      composer. Harmonist

The Collaborative International Dictionary of English v.0.48:

Harmonist \Har"mo*nist\, Harmonite \Har"mo*nite\ (-n[imac]t), n.
   (Eccl. Hist.)
   One of a religious sect, founded in W["u]rtemburg in the last
   century, composed of followers of George Rapp, a weaver. They
   had all their property in common. In 1803, a portion of this
   sect settled in Pennsylvania and called the village thus
   established, Harmony.
   [1913 Webster]