merge vs subsume

merge

verb
  • To combine into a whole. 

  • To blend gradually into something else. 

noun
  • The joining together of multiple sources. 

subsume

verb
  • To place (any one cognition) under another as belonging to it; to include or contain something else. 

  • To consider an occurrence as part of a principle or rule; to colligate 

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