foundation stone vs fundament

foundation stone

noun
  • The basis of something. 

  • A stone laid during the construction of a (usually important) building, the laying of which is usually marked by a ceremony. 

fundament

noun
  • The underlying basis or principle for a theoretical or mathematical system. 

  • Foundation. 

  • The bottom; the buttocks or anus. 

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