title: What does the colon mean in :name when using php bindParam
body: <p>The PHP manual has this example for the PDO bindParam statement:</p>
  
  <pre><code>&lt;?php
  /* Execute a prepared statement by binding PHP variables */
  $calories = 150;
  $colour = 'red';
  $sth = $dbh-&gt;prepare('SELECT name, colour, calories
      FROM fruit
      WHERE calories &lt; :calories AND colour = :colour');
  $sth-&gt;bindParam(':calories', $calories, PDO::PARAM_INT);
  $sth-&gt;bindParam(':colour', $colour, PDO::PARAM_STR, 12);
  $sth-&gt;execute();
  ?&gt;
  </code></pre>
  
  <p>Does the <code>:</code> colon just mean that <code>:colour</code> is a parameter?</p>