Beginner
Blockchain
Consensus
The process independent nodes use to agree on one canonical history without a central operator.
In simple terms
Everyone follows the same rules and follows the chain with the most accumulated weight — so even strangers end up agreeing on the same transactions.
Analogy
A room of reporters who all photographed the same event: compare the photos and the shared facts emerge, no editor required.
Going deeper
Nakamoto consensus picks the heaviest chain (PoW) or the most attested checkpoints (PoS); BFT-style protocols finalise once a supermajority signs the same block. The trade-off space — decentralisation, security, throughput — is the "blockchain trilemma".
Common mistake
Consensus does not validate real-world truth: it agrees on the rules and the history, not on whether a token deserves its price.