reinforcement vs underpinning

reinforcement

noun
  • A thing that reinforces. 

  • The process whereby a behavior with desirable consequences comes to be repeated. 

  • A small round white sticker placed around a punched hole in a piece of paper to prevent the binder's rings from tearing through the paper. 

  • Additional troops or materiel sent to support a military action. 

  • The act, process, or state of reinforcing or being reinforced. 

underpinning

noun
  • A basis for something. 

  • The lower body or legs. 

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

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