Well, lets use the word “BLOCKCHAIN” and have it include its equivalents (Tangle, Graphs, etc.).
Blockchains are programming techniques to allow AUTOMATION of task concerning monetary value without needing 3ed parties (like Banks, Brokers, Insurers, Governments, etc.) as “trusted intermediaries”. In essence it is the platform to automate ALL financial activities, putting a lot of bankers etc. out of a job.
In addition, if properly decentralized, they provide redundancy and the inability to change any records or transactions and its impossible to shut it down.