Popis riječi koje su rezervirane u jezgri PHP-a i ne možete ih koristiti u neku drugu svrhu:

and	$argc	$argv
break	case	cfunction
continue	declare	default
do	E_ALL	echo
else	elseif	empty
endfor	endforeach	endif
E_PARSE	eval	E_WARNING
extends	FALSE	for
function	$HTTP_COOKIE_VARS	$HTTP_ENV_VARS
$HTTP_POST_FILES	$HTTP_POST_VARS	$HTTP_SERVER_VARS
include	include_once	global
new	not	NULL
or	parent	PHP_OS
PHP_VERSION	print	require
return	static	stdClass
$this	TRUE	var
while	xor	_ _FILE_ _
_ _sleep	_ _wakeup	$_COOKIE
$_FILES	$_GET	$_POST
as	class	die
E_ERROR	enddeclare	endswitch
exit	foreach	$HTTP_GET_VARS
if	list	old_function
$PHP_SELF	require_once	switch
virtual	_ _LINE_ _	$_ENV
$_SERVER