Interchain refers to interaction among separate blockchains, and sometimes to the wider ecosystem built around that interaction. It is commonly associated with Cosmos and the Inter-Blockchain Communication protocol, or IBC. The idea is broader than moving a token: applications can exchange data or coordinate actions while the participating chains maintain separate states and rules.
Messages connect applications
IBC separates message transport and verification from application logic. Relayers carry packet information between chains; receiving software checks it using the configured verification mechanism. In a light-client-based connection, verification uses a representation of the other chain’s consensus state instead of simply accepting the relayer’s word.
Token transfers and remote account control are examples of applications built on this communication. Sending, receiving, and acknowledging a message are distinct stages. Timeout handling can address messages that are not delivered within the permitted period, according to the protocol.
Connectivity does not erase differences
Connected chains need not share one token, governance system, or security model. Different IBC versions and client types can have different capabilities and trust assumptions, so the interchain label does not establish a uniform guarantee.
Relayer availability, client correctness, chain security, and application permissions all affect outcomes. A working connection also does not make every asset or smart contract automatically usable on every other chain.