Blockchain vs Distributed Digital Technology (DLT)

We hear blockchain and DLT terms used interchangeably, however they are not necessarily the same.
A distributed ledger is any type of synchronized database spread across multiple sites or participants – as oppose to a centralized model of database being managed and stored on selected servers.

Blockchain technology refers to how data is stored and secured.
Blockchain is basically a database that stores transactional records in chronological order within data block structures.  The blocks are cryptographically linked to form a growing chain as new blocks are added. The Cryptographic links that form the chain are meant to impede manipulation of the recorded data in the blocks – modifications to a block in the chain breaks the integrity of the blockchain

As blockchains are also distributed, copies of the blockchain are maintained by participants of its network.

So both DLTs and blockchain technologies  are distributed type of databases. However, DLTs are not necessarily linked cryptographically in a sequence of blocks which form a chain - So not all DLTs are blockchain, but all blockchains are a type of a distributed ledger.