title: What does the variable i in for loops stand for?
body: <p>Having trouble understanding what this variable is and where it gets defined:</p>
  
  <pre><code>for i in range (0, 5):
      print i
  </code></pre>
  
  <p>Prints out number 0 - 4 like expected, but I don't understand what <code>i</code> means.</p>