In casino games, volatility (also known as variance) is a term used to describe how often you win and the average size of the payouts.
It isn't related to your overall probability of winning (RTP), but rather to how those winnings are distributed over time. For example:
High Volatility Games: These offer the potential for larger payouts, but they occur less frequently. These are recommended for players who enjoy chasing "big wins" and have a larger bankroll to sustain dry spells.
Low Volatility Games: These offer more frequent wins, but generally for smaller amounts. These are ideal for longer play sessions and more consistent returns.