title: What do closures mean exactly?
body: <p>I've read about closures many times <a href="https://stackoverflow.com/questions/111102/how-do-javascript-closures-work">here</a>.</p>
  
  <p>But I'm really confusing to know exactly what do closure mean?</p>
  
  <ul>
  <li>Is variable a closure ?</li>
  <li>Or, is function is a closure ?</li>
  <li>Or, both can be called a closure ?</li>
  </ul>