A blockchain fork occurs when there is a split in the blockchain network, creating two separate chains, often due to differing opinions within the community regarding protocol changes or upgrades. Forks can be classified as either soft forks, which maintain compatibility with the original chain, or hard forks, which result in a new, incompatible version. Both types can lead to the creation of new cryptocurrencies and affect the existing ecosystem. Understanding forks is essential for investors and users navigating the rapidly evolving blockchain landscape.