http://www.htta.net/table-tennis-ping-pong-difference/
Whats the difference between ping pong and table tennis?
I read somewhere while playing ping pong, you hit your side of the table every time while in table tennis you only hit your side during the serve. Is there a difference and what is it?
‘Ping Pong’ and ‘Table Tennis’ are often used interchangeably. There is no difference in rules, however, table tennis is the official name of the sport, and is therefore always used for organization names, tournaments and the Olympics. This is because ‘Ping Pong’ is trademarked.
Table Tennis : Difference in Ping Pong Balls