fur coat vs placenta

fur coat

noun
  • The fur of an animal; the animal coat of its own fur. 

  • An outer garment for the upper body made of furry animal hides. 

placenta

noun
  • An organ in most mammals during gestation that supplies food and oxygen to the foetus and passes back waste. It is on wall of the uterus and links to the foetus through the umbilical cord. It is expelled after birth. 

  • In flowering plants, the part of the ovary where ovules develop; in non-flowering plants where the spores develop. 

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