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What is a fork?
A fork is a change to a blockchain's rules, or a split where two versions of the chain continue. A soft fork stays compatible with older software; a hard fork does not, and if some users reject it, two separate chains result, as with Ethereum and Ethereum Classic.
What it means for you
After a split, people who held coins at that moment usually hold them on both chains, but each exchange and wallet decides separately whether to support the new coin. A site asking for your seed phrase to 'claim' fork coins can take everything on both chains.
Sources: Bitcoin developer glossary, ethereum.org: The history of Ethereum · checked 4 October 2026
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