The literal meaning of the term, ‘immutable’ stands for data that cannot be changed or modified, once it has been created. Immutability is the core principle that defines the blockchain altogether. A blockchain network is immutable since all need to come to a consensus prior to validating the data.
The primary selling point of the blockchain is that it is a distributed ledger technology (DLT). This ensures that once the data is added to the blockchain, it cannot be changed by any individual whatsoever. Immutability is achieved in the blockchain with the help of cryptographic hashing.