Definition
In blockchain context, a fork occurs when the chain splits into two or more branches. Temporary forks happen naturally when two miners find blocks nearly simultaneously; these resolve quickly via the longest chain rule. Permanent forks result from protocol changes where some nodes follow new rules.
Forks come in two types: soft forks (backward-compatible rule tightening) and hard forks (backward-incompatible rule changes). Bitcoin’s history includes several notable forks, including the Bitcoin Cash hard fork in 2017.
In Simple Terms
A split in the blockchain into two paths. Can be temporary from competing blocks or permanent from rule changes.
A divergence in the blockchain where the chain splits into two paths. Can be temporary (competing blocks) or permanent (protocol changes).