Distributed Ledger
A database kept in identical copies by many independent operators and updated by an agreed rule rather than by one owner.
The defining properties are replication and a deterministic update rule: every operator applies the same transactions in the same order and arrives at the same result, so no single participant can quietly rewrite a record. A blockchain is one design for a distributed ledger, but not the only one; some systems arrange records in a directed acyclic graph, and permissioned ledgers such as Hyperledger Fabric or R3 Corda restrict participation to identified institutions. The wider term is common in banking and regulatory documents, where the concern is shared record keeping rather than a public asset. Readers meet it in central bank research, settlement pilots, and standards work.
In practice
Interbank settlement pilots have used permissioned distributed ledgers where each participating bank runs a node and membership is controlled by the operator of the network.
The common misunderstanding
Distributed does not mean public or permissionless; many distributed ledgers are operated by a closed set of known institutions that can change the rules together.