SWIFT

SWIFT (the Society for Worldwide Interbank Financial Telecommunication) is a Belgium-based network that lets more than 11,000 banks and financial institutions across the world send standardised, secure messages: "pay this amount to this account". It does not move money itself; it carries the instructions that make the money move.

Being cut off from SWIFT is a serious blow, which is why it has been used as a sanctions weapon, most notably against several Russian banks in 2022. Your bank's SWIFT (or BIC) code is what you give someone to receive an international transfer.