Кому будет интересно как получить term 3 уровня
<? $args = array( 'post_type' => 'novosti', 'taxonomy' => 'brands', );
$args_brands = array( 'orderby' => 'name', 'hide_empty' => 1 );
$all_categories = get_terms('brands', $args_brands );
$third_level = array_filter($all_categories, function ($t) { return $t->parent != 0 && get_term($t->parent, 'brands')->parent != 0;});
$third_level_ids = array_map(function ($t) { return $t->term_id;}, $third_level);
if($third_level){ foreach ($third_level as $third_lev){ ?>