RTP is short from Return to Player. It indicates what part of the winnings will be returned to the player over time. Let us give an instance: if you bet $100, and the RTP is 90%, you should expect to get a RTP of $90. Please note that the RTP is calculated for the long term, but it can be altered by developments in the short term. To avoid losing a lot, you should bet only the amount that will not make a serious dint on your finances. Keep to that principle even when the RTP is high.