preg_match and $ sign in PHP5

Hi, I have a regular expression check as: preg_match("/$xyz/", $data, $matches); And, as you know $xyz means "string starts with xyz". But somehow PHP 5 is interpreting this as variable xyz, and gives the notice below. You can ignore the message, but now it matches everything that has xyz, i.e. aaxyzbb PHP Notice: Undefined variable: xyz in /tmp/test.php Any idea about how I can specify "string starts with xyz" or fix it such that PHP5 won't recognize this as a variable? Thanks...