WORKING DEFINITION
A block contains an ordered set of transactions. It is cryptographically linked to the preceding block, and in turn it is linked to be subsequent blocks. The first block in such a chain of blocks is called the genesis block. Blocks are created by the ordering service, and then validated and committed by peers.
https://hyperledger-fabric.readthedocs.io/en/latest/glossary.html
A block contains one or more transactions. The contents of the block are not encrypted in the blockchain. A block, in general, contains valid and invalid transactions. However invalid transactions have no effect on the State.
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