Show one of the taxonomies always as default

by 

$tax_slug = 'departments';
$tax_term = 'first-department';
// get taxonomy by slug and term
$tax_args = array( $tax_slug => $tax_term );
// merge your args, with the tax args
$args = array_merge( $args, $tax_args );

// Get term object
$term_title = get_term_by( $tax_term, '', $tax_slug );

// Display Title/Headline
echo "<h2>{$term_title->name}</h2>";