How to pull the value of a taxonomy term into the html.tpl.php files
You should use the function template_preprocess_html in your template.php.

For example.

function yourtheme_preprocess_html(&amp;$vars){
    // $tid - id of your taxonomy term
    $term = taxonomy_term_load($tid);
    $vars['head_title'] = $term-&gt;name;
}


Also, copy the html.tpl.php file to the directory in your theme, where all the template files are located. And clear cache.