Price Impact and Price Slippage are two common terms used to describe the outcome of a change in price when swapping cryptocurrency. It is important to note that these terms do not mean the same thing.
Price impact is the change in token price caused by your own trade, while price slippage is the change in token price caused by the total movement of the market.
The change in token price directly caused by your trade. Price Impact is reflected as the difference between the current market price and how your trade impacts the total liquidity in a pool.
The change in token price caused by the total movement of the entire current market. Price Slippage is reflected as the difference between the price you expect to receive after swapping vs what you actually receive after the swap is complete.