cotyledon vs endocarp

cotyledon

noun
  • The leaf of the embryo of a seed-bearing plant; after germination it becomes the first leaves of the seedling. 

  • Each of the patches of villi on the foetal chorion in the placenta of ruminants and some other mammals. 

endocarp

noun
  • The woody inner layer of the pericarp of some fruits that contains the seed. 

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