federation vs unification

federation

noun
  • Act of joining together into a single political entity. 

  • Any society or organisation formed from separate groups or bodies. 

  • A collection of network or telecommunication providers that offer interoperability. 

  • Array of nations or states that are unified under one central authority which is elected by its members. 

adj
  • Of an architectural style popular around the time of federation. 

unification

noun
  • The state of being unified. 

  • Given two terms, their join with respect to a specialisation order. 

  • The act of unifying. 

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