Transaction: A transaction represents a transfer of value.
This can be money, merchandise, medical records, and so on.
Block: A miner extracts a block, which is then filled with transactions and added to the blockchain.
A block is extracted based on its key, which is composed of the following properties:
index: the current index of the block in the blockchain.previousHash: the hash of the previous block in the blockchain.
hash: the current hash of the block.
nonce: The magic number that is incremented to find the secret hash used to sign the block.
transactions: a list of transactions added to the block.
Blockchain: A blockchain represents the list of linked blocks.
A blockchain is immutable, which means that once the block is added to the blockchain, it cannot be modified.