overburden vs rim

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. 

rim

noun
  • A membrane. 

  • A wheelrim. 

  • An edge around something, especially when circular. 

  • A semicircular copydesk. 

verb
  • To form a rim on. 

  • To roll around a rim. 

  • To lick the anus of a partner as a sexual act. 

  • To follow the contours, possibly creating a circuit. 

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