A node refers to an individual computer system that forms part of a network. In cryptocurrency networks, distributed nodes validate and relay transaction data in place of a central authority. This decentralization removes any single point of failure, increasing the network's overall resilience.
Nodes each run a similar open-source software implementation and store either a complete or partial copy of the network's total transaction history. They compare newly submitted transactions with their own record to confirm their validity. Nodes also enforce network rules by rejecting blocks of transactions from miners following a different ruleset.