# Fork

> A change to a blockchain's rules. Sometimes minor, sometimes big enough to split the network in two.

Canonical URL: https://fudfomo.co/glossary/fork
Source: What The Block! Dictionary v1.0 (last updated 2026-04-25), browsable at https://wtb.fudfomo.co.

## Definition

A fork is any update to a blockchain's rules. A small change that everyone agrees on is called a soft fork. A larger change that is not backwards compatible is called a hard fork.

If the community is split on a hard fork, the chain itself can split into two separate networks, each with its own coin going forward. Bitcoin Cash splitting from Bitcoin in 2017 is a famous example.

## Related terms

- [Hard Fork](https://fudfomo.co/glossary/hard-fork): A blockchain rule change that is not backwards compatible. Old software cannot follow the new chain.
- [Soft Fork](https://fudfomo.co/glossary/soft-fork): A blockchain rule change that is backwards compatible. Old software still works, just with fewer features.
- [Consensus](https://fudfomo.co/glossary/consensus): The way a blockchain's computers agree on which transactions are valid and which version of the ledger is correct.

## 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