Glossary
Slippage
The difference between the expected price of a trade and the price actually executed, caused by limited liquidity or a price move during execution.
On an AMM, a large swap moves the pool's price along the curve, so the average price you receive is worse than the quoted spot. On any exchange, latency between deciding to trade and executing it gives the price time to move.
Wallets and DEX aggregators let you set a slippage tolerance — the maximum acceptable deviation before the transaction reverts. Setting it too tight wastes gas on failed trades; setting it too loose invites sandwich attacks.