Public Visibility

The public keyword is part of the three keywords to define visibility of a method, property or constant. It is the lowest level of visibility : it doesn’t restrict usage.

public is also the default visibility when it is omitted.

<?php

class x {
     // public constant
    const X = 1;
    public $p = 2;
}

$x = new x;
echo $x->p;
echo x::X;

?>

Documentation

Related : Final Keyword, Visibility, Private Visibility, Protected Visibility, Var