Distributed ledger technology (DLT) comprises systems that let multiple independent parties update and verify a common record without depending on one central database. Through agreed validation and data-sharing procedures, participants can keep matching or otherwise coordinated copies of transaction information. Blockchain is one implementation of DLT, which is used in financial services and other fields.
Source: European Central Bank (ECB) (source). This glossary entry is an independently worded adaptation of the cited information.