Settlement

"Settlement" means that once processed, payments are final and irrevocable.

Real-time gross settlement (RTGS) are specialist funds transfer systems where the transfer of money or securities takes place from one bank to another on a "real time" and on a "gross" basis. Settlement in "real time" means a payment transaction is not subjected to any waiting period, with transactions being settled as soon as they are processed. "Gross settlement" means the transaction is settled on one-to-one basis without bundling or netting with any other transaction.¹

RTGS systems are typically used for high-value transactions that require and receive immediate clearing. In some countries the RTGS systems may be the only way to get same day cleared funds and so may be used when payments need to be settled urgently. However, most regular payments would not use a RTGS system, but instead would use a national payment system or network that allows participants to batch and net payments

RTGS systems are usually operated by a country's central bank as it is seen as a critical infrastructure for a country's economy

[1] https://en.wikipedia.org/wiki/Real-time_gross_settlement