Buyback-and-burn is a tokenomics mechanism where protocol revenue is used to buy native tokens on the open market and permanently destroy (burn) them. This reduces circulating supply, theoretically supporting token price. It's analogous to corporate stock buybacks.
Buyback effectiveness depends on revenue scale relative to market cap. A $10M annual buyback against a $5B market cap moves the price 0.2% per year. Marketing copy frequently overstates buyback impact by quoting absolute dollar amounts without comparing to outstanding supply.