title: What is "context menu" & method registerForContextMenu()
body: <p>In <strong>Activity</strong> class, there is method called <code>registerForContextMenu(View view)</code>.</p>
  
  <p>The android document explains that this method is used to registers a <strong>context menu</strong> to be shown for the given view (multiple views can show the context menu).</p>
  
  <ul>
  <li>What does "<strong>context menu</strong>" mean? Does it mean the physical menu button or what?</li>
  <li>I also need some explanation about the method <code>registerForContextMenu(View view)</code>, it is not clear to me to just read the document online.</li>
  </ul>