pistachio vs pistachio nut

pistachio

noun
  • A pale green colour, like that of a pistachio seed. 

  • The nutlike fruit of this tree. 

  • A deciduous tree (Pistacia vera) grown in parts of Asia for its drupaceous fruit. 

pistachio nut

noun
  • pistachio 

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