Node
A computer that maintains a copy of the blockchain and participates in validating and relaying transactions. Full nodes store and verify the complete blockchain history independently. Light nodes store only block headers for efficiency. Archive nodes retain every historical state of the blockchain. The more nodes a network has, the more decentralized and resilient it becomes.
“Running a Bitcoin full node lets you independently verify all transactions without trusting any third party. Anyone can run a node with modest hardware and a few hundred GB of storage.”
Blockchain
A distributed, append-only digital ledger that records transactions across a network of computers in a way that makes it cryptographically secured and practically impossible to alter historical records. Each block contains transaction data and is linked to the previous block through a cryptographic hash, forming an immutable chain.
Validator
A network participant in a Proof of Stake blockchain that is responsible for proposing new blocks, attesting to the validity of blocks proposed by others, and maintaining the integrity of the network. Validators must stake a minimum amount of the native token as collateral and run node software continuously. They earn rewards for honest participation and face slashing penalties for misbehavior.
Decentralization
The distribution of control, authority, and data processing across a network of participants rather than concentrating it in a single entity. In blockchain, decentralization means no single party controls the network, making it censorship-resistant and reducing single points of failure.
Consensus Mechanism
The method by which a decentralized blockchain network reaches agreement on the current state of the ledger and which transactions are valid. Consensus mechanisms solve the problem of coordinating untrusting parties without a central authority. Major types include Proof of Work, Proof of Stake, Delegated Proof of Stake, and Proof of Authority.