citron vs cucumber

citron

noun
  • The candied rind of the citron fruit. 

  • The fruit of a citron tree. 

  • A greenish yellow colour. 

  • A small citrus tree, Citrus medica. 

adj
  • Of a greenish yellow colour. 

cucumber

noun
  • The edible fruit of this plant, having a green rind and crisp white flesh. 

  • A vine in the gourd family, Cucumis sativus. 

  • A person who is calm and self-possessed. 

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