achene vs cascabel

achene

noun
  • A small, dry, indehiscent fruit, containing a single seed, as in the buttercup. 

cascabel

noun
  • A small, round, hot variety of chili pepper, Capsicum annuum, which rattles when dry. 

  • A knob at the end of a cannon, cast onto the gun breech, to which a heavy rope is attached in order to control recoil. 

  • A bell attached to a sleigh or sleigh harness. 

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