You can use single_term_title()
:
<h3><?php single_term_title(); ?></h3>
To hide it if there are no posts, use the if ( have_posts() ) :
function:
<?php if ( have_posts() ) : ?>
<h3><?php single_term_title(); ?></h3>
<?php endif; ?>
If not an archive, you can use get_term_by()
to get the term object for the term and then echo the name:
$term = get_term_by( 'slug', 'book-1-chapter-1', 'book' );
?>
<h3><?php echo $term->name; ?></h3>