collaboration vs confederacy

collaboration

noun
  • The act of collaborating. 

  • Treasonous cooperation. 

  • A production or creation made by collaborating. 

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 collaboration and confederacy occurred in a corpus of books? (source: Google Ngram Viewer )