Source : Webster's Revised Unabridged Dictionary (1913)

Gittern \Git"tern\, v. i.
   To play on gittern. --Milton.

Gittern \Git"tern\, n. [OE. giterne, OF. guiterne, ultimately
   from same source as E. guitar. See {Guitar}, and cf.
   {Cittern}.]
   An instrument like a guitar. ``Harps, lutes, and giternes.''
   --Chaucer.

Source : WordNet®

gittern
     n : a 16th century musical instrument resembling a guitar with a
         pear-shaped soundbox and wire strings [syn: {cittern}, {cithern},
          {cither}, {citole}]