coterie vs sorority

coterie

noun
  • A circle of people who associate with one another for a common purpose. 

  • A communal burrow of prairie dogs. 

sorority

noun
  • A group of girls or women associated for a common purpose; a sisterhood. 

  • A social organization of female students at a college or university; usually identified by Greek letters. 

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