Node

A node in a blockchain network is a computer or device that is connected to the network and participates in the consensus and validation process of the blockchain. Nodes can take on different roles depending on the type of blockchain and its consensus mechanism.

In a decentralized blockchain network like Bitcoin or Ethereum, nodes are typically run by individuals or entities who are collectively responsible for maintaining the integrity of the blockchain. These nodes typically have a copy of the entire blockchain and validate new transactions and blocks before adding them to the blockchain.

In a permissioned blockchain, nodes are typically controlled by a centralized organization or group of organizations and have more restricted roles and permissions. These nodes may only have access to a subset of the data on the blockchain, and may only be able to validate transactions or add new blocks under certain conditions.

In summary, a node is a device or computer connected to the blockchain network, and its role is to validate transactions and add new blocks to the chain, maintaining the integrity of the blockchain.