DLT vs blockchain
They are similar but not the same.
Both are developed to record information in a way that makes it impossible or difficult to change, hack, or cheat the system.
Both are referred to as record of info that is distributed around the world or people
Both are generally decentralised which isn’t governed central person or body, but ledger has certain restrictions and you cannot see all transactions whereas blockchain is completely open and transparent.
Ledgers tend to be used in banking systems whereas blockchains are used for crypto currencies.