Definition
Cross-chain refers to interaction between otherwise separate blockchains. This can involve messages, asset representations or coordinated transactions. It is a broad description of functionality, not one protocol or a guarantee that networks share the same security.
Common Approaches
A bridge may verify an event on one chain before permitting an action on another. Some designs use external validators or custodians; others rely on proofs or light-client verification. Asset transfers may involve locking and minting, burning and releasing, or moving available liquidity. A cross-chain swap exchanges assets on different chains and may use a different mechanism from bridging a token representation.
Key Considerations
The receiving chain needs a way to decide whether an external event is trustworthy. That verification method, together with finality assumptions and operator permissions, defines important risks. Delays or reorganizations on one network can affect activity on another. Cross-chain interfaces should make network, token and fee details clear, because similar names and addresses do not mean that assets are interchangeable or recoverable through the same process.