Change WooCommerce text string "Order #" to "Internet Order #"

Seems like it should be simple, but I can’t figure out how to change the strings "Order #" in emails or "Order Number" in Thank You page.

I want both to read "Web Order #" and "Web Order Number" respectively.

I have tried:

add_filter( 'gettext', 'translate_woocommerce_strings', 999, 3 );

function translate_woocommerce_strings( $translated, $untranslated, $domain ) {
   if ( ! is_admin() && 'woocommerce' === $domain ) {
      switch ( $translated) {
         case 'Order' :
            $translated = 'Web Order';
            break;
      }
   }     
   return $translated;
 }