chela vs fingernail

chela

noun
  • A pincer-like claw of a crustacean or arachnid. 

  • A pupil or disciple, especially in Hinduism. 

fingernail

noun
  • The hard, flat translucent covering near the tip of a human finger, useful for scratching and fine manipulation. 

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