title: What is 'define' used for in JavaScript (aside from the obvious)?
body: <p>I have searched high and low for documentation on this, but I just cannot find anything anywhere.</p>
  
  <p>I am using Aloha and want to use their sidebar prototype to create a new side bar of my own attached to other plugin functionality.</p>
  
  <p>Their sidebar.js starts off with this, but I can't for the life of me find any documentation that explains what it means.</p>
  
  <pre><code>define( [
      'aloha/core',
      'aloha/jquery',
      'aloha/selection'
  ], function (Aloha, jQuery, Selection, Plugin) {
  </code></pre>
  
  <p>It then goes on in that wrapper to define a bunch of functions, so <code>vars</code> and some <code>proptotypes</code>- which I can just about get my head around...</p>
  
  <p>What is that saying or where can I find an explanation?</p>