Get Term-ID

<?php

$meta = get_option('select_name');
if (empty($meta)) $meta = array();
if (!is_array($meta)) $meta = (array) $meta;
$meta = isset($meta['77']) ? $meta['77'] : array();
$value = $meta['select_field'];
echo $value; // if you want to show

?>

How can i replace the “77” with the current term id of the site?
Maybe someone can help me.

thank you!