What is a blockchain, in plain words?

A list of who owns what, held by thousands of computers at once so no single one can rewrite it.

A bank keeps a private list of who has what. You see your own line of it and trust the bank for the rest.

A blockchain is the same kind of list, except every participant holds a full copy and anyone can read all of it. New entries arrive in batches — blocks — and every copy has to agree on the order. Editing a line that is already in there would require disagreeing with thousands of other copies at once, which is what makes it practically impossible.

That is the entire invention. Not the coins, not the price: a ledger nobody owns, kept honest by the fact that no single party holds it.

Everything else follows from that. There is no support desk because there is no company. Nothing can be reversed because rewriting is the one thing the design prevents. And your ownership is a key rather than an account, because a shared list has no way to know your name.

What crypto actually is takes it from here.

Last checked 19 Oct 2026.