Data blocks are units of data storage that group related information together. They are commonly used in databases and file systems to efficiently manage and retrieve data. Each block typically contains a fixed amount of data, which helps optimize performance and reduce fragmentation. In the context of blockchain technology, data blocks are essential for maintaining a secure and transparent ledger. Each block contains a list of transactions, a timestamp, and a reference to the previous block, forming a chain. This structure ensures that once data is recorded, it cannot be altered without consensus from the network, enhancing security and trust in the system.