The term stake in poker refers to the size of the game, either by meaning initial buy-in for the tournament or blind levels in cash games.
For example, the stakes in a poker cash game can be $5/$10, meaning that you will be playing in a game with a $5 small blind and a $10 big blind. In MTTs, a $200 event means that you have to pay this fixed amount to sit down and play. Stakes are essential in determining a player’s ROI.