• a digital database containing information (such as records of financial transactions) that can be simultaneously used and shared within a large decentralized, publicly accessible network

• also - the technology used to create such a databaseThe technology at the heart of bitcoin and other virtual currencies, blockchain is an open, distributed ledger that can record transactions between two parties efficiently and in a verifiable and permanent way.     — Marco Iansiti and Karim R. Lakhani

            Definition of blockchain from Merriam-Websters.com. (c) 2022. March 3, 2022