divan vs futon

divan

noun
  • A couch- or sofa-like piece of furniture made of a mattress lying against the wall and either on the floor or an elevated structure. 

  • The council chamber where this court is held; (by extension), any court of justice. 

  • A Muslim council of state, specifically that of viziers of the Ottoman Empire that discussed and recommended new laws and law changes to a higher authority (the sultan). 

  • A collection of poems, especially one written by an author in Arabic or Persian. 

futon

noun
  • A specific kind of sofa-bed, with a fixed cushion that forms a mattress when folded down and a sofa when folded up. 

  • A round cushion used for Zen meditation, traditionally made of woven bulrush leaves. 

  • A thin mattress of tufted cotton or similar material, placed on a floor or on a raised, foldable frame as a bed. 

How often have the words divan and futon occurred in a corpus of books? (source: Google Ngram Viewer )