break down vs overburden

break down

verb
  • To render or to become weak and ineffective. 

  • To demolish, to pull down. (intentionally) 

  • To divide into parts to give more details, to provide a more indepth analysis of. 

  • To (cause to) decay, to decompose. 

  • To cease to function. (others) 

  • To stop functioning. (machine, computer, vehicle) 

  • To fail, especially socially or for political reasons. 

  • To give in, relent, concede, or surrender. 

  • To digest. 

  • To render or to become unstable due to stress, to collapse physically or mentally. 

  • To collapse, physically or in structure. (unexpectedly) 

overburden

verb
  • To overload or overtax. 

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. 

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