RTP describes the share of stakes a game is designed to return over a very...

https://wiki-site.win/index.php/How_Do_UK_Casinos_Make_RTP_Info_More_Transparent%3F

RTP describes the share of stakes a game is designed to return over a very large number of plays. A 96% RTP means a 4% house edge on average—not that you’ll get 96% back in one session