better vs upgrade

better

verb
  • To improve. 

  • To surpass in excellence; to exceed; to excel. 

  • To give advantage to; to support; to advance the interest of. 

  • Had better. 

  • To become better; to improve. 

noun
  • An entity, usually animate, deemed superior to another; one who has a claim to precedence; a superior. 

adj
  • Greater in amount or quantity 

adv
  • Greater or lesser (whichever is seen as more advantageous), in reference to value, distance, time, etc. 

  • Had better. 

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 better and upgrade occurred in a corpus of books? (source: Google Ngram Viewer )