chayote vs courgette

chayote

noun
  • The fruit of this plant. 

  • Sechium edule, a tropical American perennial herbaceous vine having tendrils, tuberous roots, and a green, pear-shaped fruit cooked as a vegetable. 

courgette

noun
  • The edible fruit of this marrow/squash. 

  • A particular variety of Cucurbita pepo, a small marrow/squash. 

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