annexation vs confluence

annexation

noun
  • A legal merging of a territory into another body. 

  • Addition or incorporation of something, or territories that have been annexed. 

confluence

noun
  • The act of combining that occurs where two rivers meet. 

  • The stream or body formed by the junction of two or more streams; a combined flood. 

  • A convergence or combination of forces, people, or things. 

  • The place where two rivers, streams, or other continuously flowing bodies of water meet and become one, especially where a tributary joins a river. 

  • The proportion of cells, in a culture medium, that adhere to each other. 

  • A property describing which terms can be rewritten with other, equivalent terms. 

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