confederation vs indivisibility

confederation

noun
  • A union or alliance of states or political organizations. 

  • The act of forming an alliance. 

indivisibility

noun
  • The state of being indivisible. The state incapable of being divided. 

  • An indivisible factor or object. 

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