What does $$ (dollar dollar or double dollar) mean in PHP?

A syntax such as $$variable is called Variable Variable.

For example, if you consider this portion of code:

$real_variable="test";
$name="real_variable";
echo $$name;

You will get the following output:

test

Here:

• $real_variable contains 'test'
• $name contains the name of your variable: 'real_variable'
• $$name mean “the variable thas has its name contained in $name”
  • Which is $real_variable
  • And has the value 'test'

EDIT after @Jhonny’s comment:

Doing a $$$?
Well, the best way to know is to try 😉

So, let’s try this portion of code:

$real_variable="test";
$name="real_variable";
$name_of_name="name";

echo $name_of_name . '<br />';
echo $$name_of_name . '<br />';
echo $$$name_of_name . '<br />';

And here’s the output I get:

name
real_variable
test

So, I would say that, yes, you can do $$$ 😉