prep school vs state school

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. 

state school

noun
  • A government-funded school, paid for by taxes. 

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