overburden vs pressure

overburden

noun
  • A sterile stratum that lies above the stratum being investigated 

  • The rock and subsoil that lies above a mineral deposit such as a coal seam. 

verb
  • To overload or overtax. 

pressure

verb
  • To encourage or heavily exert force or influence. 

noun
  • A pressing; a force applied to a surface. 

  • Distress. 

  • The amount of force that is applied over a given area divided by the size of this area; force per unit area. 

  • A contrasting force or impulse of any kind 

  • Urgency 

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