richen vs upgrade

richen

verb
  • To become rich or richer; become superior in quality, condition or effectiveness. 

  • To make or render rich or richer. 

  • To gain richness; become heightened or intensified in brilliancy. 

upgrade

verb
  • To improve in condition or status. 

  • To improve, usually applied to technology, generally by complete replacement of one or more components 

  • To replace with something better. 

  • To improve the equipment or furnishings of or services rendered to 

  • To replace a program with a later version of itself, a version having a higher version number or marketed under a more recent product name. 

adv
  • Up a slope or grade. 

noun
  • An upward grade or slope. 

  • An improvement 

  • An improved component or replacement item, usually applied to technology 

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