PHP Constants Containing Arrays?

Since PHP 5.6, you can declare an array constant with const:

<?php
const DEFAULT_ROLES = array('guy', 'development team');

The short syntax works too, as you'd expect:

<?php
const DEFAULT_ROLES = ['guy', 'development team'];

If you have PHP 7, you can finally use define(), just as you had first tried:

<?php
define('DEFAULT_ROLES', array('guy', 'development team'));

NOTE: while this is the accepted answer, it's worth noting that in PHP 5.6+ you can have const arrays - see Andrea Faulds' answer below.

You can also serialize your array and then put it into the constant:

# define constant, serialize array
define ("FRUITS", serialize (array ("apple", "cherry", "banana")));

# use it
$my_fruits = unserialize (FRUITS);