- NT: genesis block
No definition in earlier IP projects. ITrust definition not yet developed.
- Back et al. 2010 (†832 s.v. "3.1 Definitions"): A block is a collection of transactions describing changes in asset control.
- Bitcoin Developer Glossary 2017 (†791 s.v. "Block"): One or more transactions prefaced by a block header and protected by proof of work. Blocks are the data stored on the block chain.
- Bitcoin Wiki Vocabulary  (†796 s.v. "Block"): Transaction data is permanently recorded in files called blocks. They can be thought of as the individual pages of a city recorder's recordbook (where changes to title to real estate are recorded) or a stock transaction ledger. Blocks are organized into a linear sequence over time (also known as the block chain). New transactions are constantly being processes by miners into new blocks which are added to the end of the chain and can never be changed or removed once accepted by the network (although some software will remove orphaned blocks). · Each block contains, among other things, a record of some or all recent transactions, and a reference to the block that came immediately before it. It also contains an answer to a difficult-to-solve mathematical puzzle - the answer to which is unique to each block. New blocks cannot be submitted to the network without the correct answer - the process of "mining" is essentially the process of competing to be the next to find the answer that "solves" the current block. The mathematical problem in each block is extremely difficult to solve, but once a valid solution is found, it is very easy for the rest of the network to confirm that the solution is correct. There are multiple valid solutions for any given block - only one of the solutions needs to be found for the block to be solved.
- BlockchainHub Glossary (†807 s.v. "Block (on the Bitcoin Blockchain)"): Data is permanently recorded in the Bitcoin network through files called blocks. A block is a record of some or all of the most recent Bitcoin transactions that have not yet been recorded in any prior blocks. New blocks are added to the end of the record (known as the blockchain), and can never be changed or removed once written (although some software will remove them if they are orphaned). Each block memorializes what took place in the minutes before it was created. Each block contains a record of some or all recent transactions and a reference to the block that came immediately before it. It also contains an answer to a difficult-to-solve mathematical puzzle – the answer to which is unique to each block. New blocks cannot be submitted to the network without the correct answer – the process of “mining” is essentially the process of competing to be the next to find the answer that “solves” the current block.
- Condos et al. 2016 (†819 p.6): Each set of transactions (the number of which is prescribed by the protocol) is considered a block in the chain, and the register as a whole is the blockchain. This chain is stored and continually added to by a network of computers, each of which is known as a node.
- ISO TC307 (Japan). 2017 (†857 s.v. "3.5 block" ; p.9): data container used by blockchain.
- ISO TC307 N55 (France). 2017 (†858 ): Set of timestamped transactions prefaced by a block header.
- ISO TC307 N67 (United Kingdom). 2017. (†841 p.1): batch of ordered transactions, potentially containing ones of an invalid nature, that is delivered to the peers for validation and committal.
- Pfeffer  (†844 s.v. "Block"): A Block is the basic element of a Blockchain. It functions as a journal, recording a series of transactions together with a reference to the previous Block. A Block is chained to its preceeding Block by a cryptographic hash as a means of reference. Blocks contain an identifier for the final state after all transactions contained in it are validated. There is an incentive mechanism that provides incentives to generate new Blocks ("mine Blocks") that comply to the rules of Ethereum by issuing a reward to an Account specified by the miner.
- Scaling Bitcoin  (†845 s.v. "Block"): A block is a permanent record of data stored in the blockchain, acting like a page or ledger. Each block contains and confirms pending transactions. Roughly every 10 minutes, on average, a new block along with the transactions it contains is added to the blockchain through mining.
- Buterin  (†818 s.v. "Mining"): Bitcoin's decentralized consensus process requires nodes in the network to continuously attempt to produce packages of transactions called "blocks". The network is intended to create one block approximately every ten minutes, with each block containing a timestamp, a nonce, a reference to (i.e., hash of) the previous block and a list of all of the transactions that have taken place since the previous block. (†2176)
- Wood 2014 (†803 p.5): The block in Ethereum is the collection of relevant pieces of information (known as the block header), H, together with information corresponding to the comprised transactions, T, and a set of other block headers U that are known to have a parent equal to the present block's parent's parent (such blocks are known as ommers). (†2173)