drupe vs seed pit

drupe

noun
  • a kind of fruit, with a fleshy exterior, formed from the exocarp and mesocarp, surrounding a hardened endocarp which protects the seed. 

seed pit

noun
  • A single seed in the center of a cherry, peach, plum, olive, avocado or other fruit. 

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