A blockchain is a distributed and shared database register which has the function of creating a global index of all transactions in a specific market.
It works as a ledger but in a public sense, shared and universal, creating consensus and trust in direct communication between two parties without the need of a third one.
It’s in a constant growth as new complete blocks are added through a new set of registers.
Blocks are added to the blockchain in a linear and chronological way. Each knot – any computer that, by being linked to this chain, has the duty to validate and pass on the transactions – obtains a copy of the blockchain after it is introduced into the net. The blockchain has the complete information about your address and balances directly from the block generated, all the way to the most recently concluded.