Node

A node is a computer running a blockchain's software that keeps a copy of the ledger, checks new transactions and blocks against the rules, and relays them to other nodes. A "full node" independently verifies every block from the beginning; it does not trust anyone else's word about which transactions are valid.

Nodes are different from miners or validators. Miners and validators produce blocks; nodes decide whether to accept them. If a miner produces a block that breaks the rules, such as one that creates extra coins, full nodes simply reject it. This is why many people describe users running nodes as the final enforcement of a network's rules.

Running a Bitcoin full node is possible on a modest home computer with enough storage, and lets your wallet check your own payments without relying on a third-party server.