executive branch vs oligarchy

executive branch

noun
  • The branch of government that oversees the carrying out of the laws 

oligarchy

noun
  • A state ruled by such a government. 

  • Those who make up an oligarchic government. 

  • A government run by only a few, often the wealthy. 

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