bloc vs confederacy

bloc

noun
  • A group of countries acting together for political or economic goals, an alliance: e.g., the eastern bloc, the western bloc, a trading bloc, the Eurozone, the European Union. 

  • A group of voters or politicians who share common goals. 

confederacy

noun
  • An alliance. 

  • A state where the sovereign constituent units delegate their authority to the centre. As opposed to a federation, where the central and regional governments are each equal and sovereign in their own sphere. 

  • Specifically, an instance of a decentralized governing structure among the indigenous peoples of North America. 

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