portal vs revolving door

portal

noun
  • An entrance, entry point, or means of entry. 

  • A grandiose and often lavish entrance. 

  • A short vein that carries blood into the liver. 

  • A prayer book or breviary; a portass. 

  • A lesser gate, where there are two of different dimensions. 

  • The space, at one end, between opposite trusses when these are terminated by inclined braces. 

  • Formerly, a small square corner in a room separated from the rest of an apartment by wainscoting, forming a short passage to another apartment. 

  • A website or page that acts as an entrance to other websites or pages on the Internet. 

  • A magical or technological doorway leading to another location, period in time or dimension. 

verb
  • To use a portal (magical or technological doorway). 

adj
  • Of or relating to a porta, especially the porta of the liver. 

revolving door

noun
  • A system or institution in which people exit and immediately reenter. 

  • A door that rotates around a central pivot. 

  • A movement of personnel between roles as legislators and regulators, on the one hand, and members of the industries affected by the legislation and regulation, on the other. 

  • Synonym of recidivism 

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