arrowhead vs hopniss

arrowhead

noun
  • Any plant in the genus Sagittaria. 

  • The pointed part of an arrow. 

hopniss

noun
  • Apios americana, a perennial vine that bears edible beans and large edible tubers. 

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