Definition
The mechanism by which all participants in a distributed blockchain network agree on the valid state of the ledger. Consensus ensures every node holds an identical, accurate copy of the blockchain.
Why It Matters
Consensus is what makes blockchains trustless and decentralized. Without it, the network would split or be vulnerable to fraud.
Example
Bitcoin uses Proof of Work consensus — nodes accept the longest valid chain with the most accumulated work as the truth.
Related Terms
Proof of Work
Proof of Stake
Node
Validator