What does the term 'fork' refer to in blockchain?

The term 'fork' in blockchain refers to an event where a blockchain diverges into two separate chains due to protocol changes. This typically occurs when there is a disagreement within the community or among developers about the direction of the project or specific changes to the codebase. When a fork happens, the current state of the blockchain continues on one chain, while a new version of the blockchain starts from a specific point, running on a different set of rules or features.

For example, one of the highest-profile forks occurred with Bitcoin in 2017, leading to the creation of Bitcoin Cash. This split happened because some members of the Bitcoin community wanted to increase the transaction capacity to accommodate more users, while others preferred to maintain the original blockchain's current protocols. Forks can be categorized as either hard forks, where there is a significant change that is not backward-compatible, or soft forks, which are backward-compatible.

This understanding of forks is crucial for blockchain developers, as it can affect everything from community dynamics to the technical structure of the blockchain itself. The other options provided do not accurately capture the meaning of a fork within the blockchain context.