In the context of cryptocurrency trading, slippage occurs when a trade order is executed at a different price than what was expected due to changes in the market conditions. This often happens during times of high volatility or low liquidity, where the market price can rapidly change from the time the order is placed to the time it is executed. Slippage can be either positive (where the trade executes at a better price than expected) or negative (where the trade executes at a worse price).