"Distributed ledger technology is a broad category that encompasses blockchain technology. A distributed ledger is just what its name implies. Instead of accounting for data through one centralized computer, distributed ledger technology uses many participants in a network to maintain a digital record. Blockchain technology supplements a distributed ledger with cryptographic functions and a consensus algorithm to enable greater incentive design, security, accountability, cooperation, and trust."
- From this website (26-4-2018):
"What is the difference between blockchain and DLT? It is simpler than it might appear. A blockchain, a chain of blocks, is a type of DLT. Meaning, this is a case of a common phenomenon of name recognition causing confusion: when the success of a specific service, product, or application overtakes the “umbrella” to which it belongs and ends up devouring its namesake. In the same way not all sticky notes are Post-it, not all DLTs are blockchain.
From a more technical perspective, a DLT is simply a decentralized database that is managed by various participants. There is no central authority that acts as arbitrator or monitor. As a distributed log of records, there is greater transparency – making fraud and manipulation more difficult – and it is more complicated to hack the system."