academy vs prep school

academy

noun
  • An institution for the study of higher learning; a college or a university; typically a private school. 

  • A society of learned people united for the advancement of the arts and sciences, and literature, or some particular art or science. 

  • Plato's philosophical system based on skepticism; Plato's followers. 

  • The garden where Plato taught. 

  • A school directly funded by central government, independent of local control. 

  • A body of established opinion in a particular field, regarded as authoritative. 

  • A school or place of training in which some special art is taught. 

  • Academia. 

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 academy and prep school occurred in a corpus of books? (source: Google Ngram Viewer )