embryo vs papilla

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. 

papilla

noun
  • A small fleshy projection on a plant. 

  • Any of the small protuberances on the upper surface of the tongue often containing taste buds. 

  • A vascular process of connective tissue extending into and nourishing the root of a hair, feather, or developing tooth. 

  • Any of the vascular protuberances of the dermal layer of the skin extending into the epidermal layer and often containing tactile corpuscles. 

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