Blockchain is essentially a kind of DLT. That is, all blockchains are DLTs, but not all DLTs are blockchains.

A blockchain basically adds an extra set of features to a DLT. Moreover, in a blockchain, all data is distributed to all participants and protected by a cryptographic signature called a hash. This makes the information stored in the blockchain immutable, which increases security and integrity.

Another major difference between blockchain and DLT is proof of work. Distributed ledger is comparatively more scalable as it does not need proof of work. Blockchain, on the other hand, is a subset of distributed ledger but it has additional functionality beyond the traditional DLT's scope.