viol vs viola da gamba

viol

verb
  • To play the viol. 

noun
  • A large rope used to manipulate the anchor 

  • A stringed instrument related to the violin family, but held in the lap between the legs like a cello, usually with C-holes, a flat back, a fretted neck and six strings, played with an underhanded bow hold 

viola da gamba

noun
  • Synonym of viol 

How often have the words viol and viola da gamba occurred in a corpus of books? (source: Google Ngram Viewer )