Backslash in PHP -- what does it mean?

Question

I just saw the use of a backslash in a reference to a PHP object and was curious about it (I have never seen this before). What does it mean?

$mail = new SendGridMail();

If you're curious, here's SendGrid's documentation.

Answer 1

It's because they're using PHP namespaces. Namespaces are new as of PHP 5.3.