bressummer vs underpinning

bressummer

noun
  • A large, horizontal supporting beam which bears the weight of a wall starting on a first or higher floor, particularly when exposed or used to support a jetty (timber-frame overhang construction). 

underpinning

noun
  • A support or foundation, especially as a structure of masonry that supports a wall. 

  • The lower body or legs. 

  • A basis for something. 

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