From php.net ...
Value of a constant; only scalar and null values ββare allowed . Scalar values ββare integer, float, string, or boolean. You can define resource constants, but this is not recommended and can cause unpredictable behavior.
But you can do some tricks:
define('names', serialize(array('John', 'James' ...)));
& unserialize() (). , :
define('NAME1', 'John');
define('NAME2', 'James');
..
:
echo constant('NAME'.$digit);