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