$re = '/\b(dance|ballet|design|film|(?<!liberal )(?<!culinary )(?<!language )arts?|music|photograph(ic|y)|theat(er|re)|performing|visual)\b/';
$str = 'arts
liberal arts
culinary arts
language arts
martial arts';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php