When first encountered, blockchain can seem like a complex concept to understand; however, simple words and common associations can help overcome that complexity and make blockchain into something that can be easily understood. To start off, blockchain is a distributed database, a shared record book. This is not just one record book stored in a central location that is shared by many. Instead, there are thousands of copies of this record book stored all around the world — both on home computers and on business servers (hence the term “decentralized”). This shared record book is not owned by any one individual or organization. It is owned by everyone who has a copy, meaning that any one person/organization cannot have complete control over it.
Each addition to this record book is a new line item, and every line entry made will exist in perpetuity, for as long as the internet exists. If someone tries to dishonestly modify this record book, those changes would be rejected by the many computers used in the verification process as the modified changes just would not match the other instances of the record book.
To read more details on the phenomena of blockchain and see some examples of its real-world application, access the original article.