Where is the jQuery API on `$.`?
<p>I saw this somewhere,</p>

<p>For example there is the <code>each</code> function to iterate over objects and arrays:</p>

<pre><code>$($arr).each(
function(idx)
  {
     //do stuff
  }
);
</code></pre>

<p>But then there is the format $.each($arr, function);</p>

<p>What is this "<code>$.</code>"? Does it have a name?</p>

<p>What else can you do with it?</p>
