A group of inputs, transactions, or extrinsic data, based on which Blockchain Models we are using, bundled together.
A block also contains an important header, which links it using a Cryptographically Secured Hash to a specific parent block, creating the tamper-proof property of the blockchain data structure. See Blockchains Are Overrated for more detail.
Other than linking to a parent block, the header also contains secure hashes that act as a digest or commitment to:
- What entire transactions that are in the block
- The posterior state after executing this block
These commitments, combined with State Proof, can allow anyone to securely query information about the transactions and the state of this block.