phrontistery vs prep school

phrontistery

noun
  • An establishment devoted to education or study. 

  • A place for thinking. 

  • The toilet; the lavatory. 

prep school

noun
  • A private or public school intended to prepare its students to get into prestigious universities. 

  • A private primary school which prepares its pupils for the common entrance examination most commonly at the age of thirteen, and subsequent entry into public school. 

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