Pseudo-variable

A pseudo-variable is a term used to describe a variable that looks like a variable but does not represent one. Instead, it is a special case that has a specific meaning within its context. In PHP, $this is the only pseudo-variable: it represents the object that is called.

<?php

    class X {
        private string $name;

        function __construct($name) {
            $this->name = $name;
        }

        function foo() {
            // $this represents any object of type x
            print $this->name;
        }
    }

    // $a represents only the object 'a', type x, until it is reassigned
    $a = new x('a');

    // $b represents only the object 'b', type x, until it is reassigned
    $b = new x('b');

?>

Documentation

Related : Variables