Terminology

Since there are multiple terms being used here lets clarify some so there is no confusion:

The data store that keeps all blockchain data is called a ledger. Each entry in the ledger is called a transaction. The transactions are timestamped and stored in groups of blocks.

On the ledger you can only add a new transaction or read the old ones. You can not update or delete anything.

The ledger is designed to be immutable using cryptographic algorithms (we will study in next chapter) and its distributed design. The ledger is replicated and maintained by multiple hosts or peers or nodes. This is why its called DLT or Distributed Ledger Technology.

In the next lesson, we will see a quick recap of the whole chapter.