buckwheat vs knotgrass

buckwheat

noun
  • An Asian plant, of the species Fagopyrum esculentum. 

  • Any of the wild buckwheats in the genus Eriogonum. 

  • A slow and painful murder by the Mafia as a warning to others. 

  • The fruit of this plant used as a pseudocereal. 

  • Curly hair of a black person. 

  • Pubic hair. 

knotgrass

noun
  • An annual plant, Polygonum aviculare, found in fields and wasteland 

  • Paspalum distichum, a weedy perennial grass of wet areas 

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