You can read the commented lines to understand the code, it’s quite simple!
Paste this in your taxonomy.php!
<?php //get the global term SLUG from $wp_query variable.. $term_slug = get_query_var('term'); // get all info related to that term $term_info = get_term_by( 'slug',$term_slug ,'YOUR_TAXONOMY'); // this line converts to integer the id of the parent cat! $parent = (int)$term_info->parent; //Use get_term_link() function to print the correct link to the parent taxonomy, //we also CHECK if there is any parent, otherwise, do nothing.. echo ($parent)?'<a href="'.get_term_link( $parent , 'YOUR_TAXONOMY').'">Go Back</a>':''; ?>