Overview
Miles "Tails" Prower (マイルス "テイルス" パウアー Mairusu "Teirusu" Pauā) is the full name (and nickname) of the Sonic the Hedgehog character Tails.
His real name, Miles Prower (マイルス・パウアー Mairusu Pauā), is a pun on miles per hour which means the speed per hour including the common American mileage system. The real world creator of Tails, Yasushi Yamaguchi, wanted his name to just be Miles Prower but made the compromise with using the name Tails, but as a nickname.
For more details refer to the article Tails.