product_cat
woocommerce product category
$tax_query = array( array( 'taxonomy' => 'product_cat', 'terms' => array( 'term1', 'term2' ), 'field' => 'name', ), array( 'taxonomy' => 'product_tag', 'terms' => array( 'term3', 'term4' ), 'field' => 'name', ), );