concurrency vs synchronicity

concurrency

noun
  • The property or an instance of being concurrent; something that happens at the same time as something else. 

  • A property of systems where several processes execute at the same time. 

  • A stretch of road that is shared between two or more numbered or named routes. 

synchronicity

noun
  • The state of being synchronous or simultaneous. 

  • Coincidences that seem to be meaningfully related; supposedly the result of "universal forces". 

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