frond vs petiole

frond

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

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

petiole

noun
  • The stalk of a leaf, attaching the blade to the stem. 

  • A narrow or constricted segment of the body of an insect; especially, the metasomal segment of certain Hymenoptera, such as wasps. 

  • The stalk at the base of the nest of the paper wasp. 

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