foliole vs frond

foliole

noun
  • One of the distinct parts of a compound leaf; a leaflet. 

frond

noun
  • The leaf of a fern, especially a compound leaf. 

  • Any fern-like leaf or other object resembling a fern leaf. 

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