What is Rollback?

What is Rollback? Can you explain in detail with example...

Rollback is a facility used in database management systems for some sort of security. We can use ROLLBACK TRANSACTION to erase all data modifications made from the start of the transaction or to a savepoint. It also frees resources held by the transaction. In simple words, if we made some mistakes in the data, we can rollback the transaction to make the data in its original form.