Volatility refers to the the range of expected results in a certain game or situation. For example, if game A and game B have the same RTP, but game A has high volatility and game B has low volatility, game A will have a wider range of results than game B.

In basic terms, lower volatility games are more stable and higher volatility games are unstable. The same can be said for types of bets, as bets with lower chances of hitting are more volatile than bets with higher chances of winning.