We don't have synonyms for gitterns yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are jitters, mittens and gittern.
(n) :
A small, quill-plucked, gut-strung musical instrument, most commonly with three to four strings in doubles courses; it is a flat-backed predecessor of the guitar, and it originated around the 13th century, coming to Europe via Moorish Spain.
(n) :
A small, quill-plucked, gut-strung musical instrument, most commonly with three to four strings in doubles courses; it is a flat-backed predecessor of the guitar, and it originated around the 13th century, coming to Europe via Moorish Spain.