Hash - Today's Word:

A hash is a mathematical function used to convert data into a fixed string of letters and numbers. In the world of cryptocurrencies, hashes are used to ensure the security of transactions and protect them from tampering. Each transaction or block in the blockchain contains a unique hash value that represents it, making it difficult to change or tamper with the data after it has been added to the ledger.

In short, a hash acts as a "digital signature" for each piece of data, and is used to confirm the validity of transactions and secure the network against tampering.