Definition of side pot
The "side pot" is a side pot. The side pot occurs when a player is already all in in the hand and there are still other players to talk to. If a player is all in on the turn for example, but there are still 2 players in the hand with an all-in, there will be a side pot. The player with the smallest stack will only be able to win the main prize pool. For example, if you have 20 big blinds, when you win a hand against two players who were also all in and had 100 big blinds, you won't take 100 big blinds from them, but 20 big blinds, which you risked.
An example of a side pot
Imagine a hand in which the button has 100 big blinds, the small blind has 20 big blinds and the big blind has 100 big blinds. Let's say the button opens preflop and the player in SB position decides to push all in. After the all in, both players (BTN and BB) decide to call. From here, we will build a main pot of 60 big blinds. All the money that will be invested afterwards by the button and the big blind will be sent to a side pot.