title: What's the difference between an "engine" and a "runtime"?
body: <p>I always think of an "engine" as something that is running, and therefore needs to be started and stopped. But I've also heard the term "runtime" ("Java <strong>Runtime</strong> Environment", etc.) and this also seems to imply that something is running...</p>
  
  <p>Are these one in the same, or are they different concepts? If so, how are they different and what criteria makes something an "engine" vs a "runtime"?</p>