embryo vs frond

embryo

noun
  • A rudimentary plant contained in the seed. 

  • In the reproductive cycle, the stage after the fertilization of the egg that precedes the development into a fetus. 

  • In viviparous animals, the young animal's earliest stages in the mother's body 

  • The beginning; the first stage of anything. 

  • In humans, usually the cell growth up to the end of the seventh week in the mother's body 

  • An organism in the earlier stages of development before it emerges from the egg, or before metamorphosis. 

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 embryo and frond occurred in a corpus of books? (source: Google Ngram Viewer )