Toyota uses Prius as the plural of Prius, though apparently whatever you want to use is fine with them: http://www.greenhybrid.com/wiki/index.php/Interview_wit

Toyota uses Prius as the plural of Prius, though apparently whatever you want to use is fine with them: http://www.greenhybrid.com/wiki/index.php/Interview_with_Ed_LaRocque http://www.greenhybrid.com/wiki/index.php/Interview_with_Ed_...