descent vs upgrade

descent

noun
  • A sloping passage or incline. 

  • A particular extension of the idea of gluing. 

  • A falling upon or invasion. 

  • A drop to a lower status or condition; decline. 

  • Lineage or hereditary derivation. 

  • An instance of descending; act of coming down. 

  • A way down. 

upgrade

noun
  • An upward grade or slope. 

  • An improvement 

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

verb
  • 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. 

  • To improve in condition or status. 

adv
  • Up a slope or grade. 

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