# Consensus > The way a blockchain's computers agree on which transactions are valid and which version of the ledger is correct. Canonical URL: https://fudfomo.co/glossary/consensus Source: What The Block! Dictionary v1.0 (last updated 2026-04-25), browsable at https://wtb.fudfomo.co. ## Definition Consensus is the rule set that lets thousands of computers agree on a single shared history without a central referee. The two best-known kinds are proof of work and proof of stake. A strong consensus mechanism makes it expensive to lie. That is what gives a blockchain its security and is why people pay attention to which mechanism a network uses. ## Related terms - [Proof of Work](https://fudfomo.co/glossary/proof-of-work): A way to secure a blockchain by making computers do a lot of calculation. Used by Bitcoin. - [Proof of Stake](https://fudfomo.co/glossary/proof-of-stake): A way to secure a blockchain using locked-up coins instead of computing power. Used by Ethereum. - [Node](https://fudfomo.co/glossary/node): A computer that helps run a blockchain by storing the ledger and checking new transactions. - [Validator](https://fudfomo.co/glossary/validator): A participant in a proof-of-stake network who proposes and confirms new blocks. Earns rewards and can be slashed. ## See the full catalogue What The Block! covers more than 2,000 plain-English crypto terms, delivered as embeddable hover-state tooltips for crypto exchanges. https://wtb.fudfomo.co