A token burn is the intentional and permanent destruction of tokens by sending them to a verifiably inaccessible address (a burn address). Once burned, tokens can never be recovered or spent, effectively reducing the total supply.
Burns can be implemented in various ways: protocol-level automatic burns (like Ethereum's base fee burn), periodic buyback-and-burn programs funded by project revenue, or one-time burns to reduce excess supply. Each approach has different implications for tokenomics.
The effectiveness of token burns depends on their scale relative to ongoing emissions. A project that burns 1% of supply annually while emitting 5% through staking rewards is still inflationary. Net supply change (emissions minus burns) is the metric that matters.