transaction
Transaction is a group that gathers several related processes as one processing unit. As a cash flow processing in a computer system of financial institutions, it is used to control a sequence of processes as one.
The process that was performed as a transaction is ensured to be either "all success" or "all fail". For example, when a fund flow system is processed with a computer, both payment and receipt are supposed to be either "both success" or "both fail". If it "successes in a payment process but fails in a receipt", the fund for payment will float in midair.
In such cases, a transaction processing can control both payment and receipt as one transaction, and it can let one success if the other successes, and vice versa. The system to realize this is called TP monitor.