I wish someone can give me a clue.
I am actually displaying all product category (product_cat taxonomy) on single page products, displaying also childs regarding the product itself.
For instance: Product-A has Cat1-parent > Cat1-child1, Cat1-child2 => The code display them properly but also will display any other Parent Category that belongs to an another existing product.... result I get an extra parent category displaying with no childs.
So Id like to display only parent categories that belongs to the product itself.
I think I am missing some knowledge in the beginning of the code with the get_terms function
$parents = get_terms( 'product_cat' , array( 'parent' => 0 ) ); foreach( $parents as $parent ): echo '<div class="parent '.$parent->slug.'">' . $parent->name . '</div>';