Blockchain is a database (distributed ledger) that records all transactions from the very beginning of cryptocurrency creation to the present day.
Transaction records of funds over a certain period of time are compiled into "blocks," which are then linked together like a "chain" and recorded.
This is also the origin of the name.

For example, imagine a bank passbook. It doesn't matter if it's a paper passbook or an online passbook.
Information about money transactions, such as money being deposited, withdrawn, or sent to other companies, is recorded, right?
In this system, money and transaction records are managed under the authority of a bank. (This is called a centralized system.)

Blockchain is a system where there is no central authority like the banks mentioned above; instead, everyone involved in the money exchange manages the data (ledger) in a decentralized manner. (This is called a decentralized system.)

[Characteristics of Blockchain]
① Because it is decentralized, no administrator is needed.
② Data cannot be tampered with.
③ Anyone can see it, and it is highly transparent.