記事（single.php）所属する子タームのみ表示する
<?php
if ($terms = get_the_terms($post->ID, 'タクソノミー名')) {
foreach ( $terms as $term ):
if($term->parent) echo esc_html($term->name);
endforeach;
} ?>
<?php
if ($terms = get_the_terms($post->ID, 'タクソノミー名')) {
foreach ( $terms as $term ):
if($term->parent) echo esc_html($term->name);
endforeach;
} ?>