aristocracy vs viscount

aristocracy

noun
  • The nobility, or the hereditary ruling class. 

  • Government by such a class, or a state with such a government 

  • A class of people considered (not normally universally) superior to others 

viscount

noun
  • A member of the peerage, above a baron but below a count or earl. 

  • Any of various nymphalid butterflies of the genus Tanaecia. Other butterflies in this genus are called earls and counts. 

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