confluence vs separation

confluence

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

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

  • 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. 

separation

noun
  • Departure from active duty, while not necessarily leaving the service entirely. 

  • An agreement legalizing such an arrangement. 

  • An object that separates two spaces. 

  • The act of disuniting two or more things, or the condition of being separated. 

  • The act or condition of two or more people being separated from one another. 

  • The place at which a division occurs. 

  • An interval, gap or space that separates things or people. 

  • The act or condition of a married couple living in separate homes while remaining legally married. 

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