Traits

Traits are a mechanism for code reuse in single inheritance languages.

Traits define methods and properties. They are included in one or several classes by the use of use expression.

<?php

trait t {
    const CONSTANT = 1;

    private $property;

    function method();
}

class x {
    use t;
}

?>

Documentation

See also Traits are not inherited, What are traits, Some lesser known facts of Traits in PHP, When to use a trait?, The difference between Traits, Interfaces, and Abstract Classes in PHP

Related : Classes, Use