inroad vs overrun

inroad

noun
  • An advance into enemy territory, an attempted invasion; an encroachment, an incursion. 

  • Often followed by in, into, or on: initial progress made toward accomplishing a goal or solving a problem. 

overrun

noun
  • An instance of overrunning. 

  • The amount by which something overruns. 

  • An area of terrain beyond the end of a runway that is kept flat and unobstructed to allow an aircraft that runs off the end of the runway to stop safely. 

  • Air that is whipped into a frozen dessert to make it easier to serve and eat. 

verb
  • To run past; to run beyond. 

  • To infest, swarm over, flow over. 

  • To continue for too long. 

  • To carry (some type, a line or column, etc.) backward or forward into an adjacent line or page. 

  • To defeat an enemy and invade in great numbers, seizing the enemy positions conclusively. 

  • To abuse or oppress, as if by treading upon. 

  • To run past the end of. 

  • To go beyond; to extend in part beyond. 

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