Multi-signature, or multisig, is a type of digital signature scheme that allows more than one person to sign a document or a transaction. It is a way of creating a joint account or a shared wallet, where multiple people must sign a transaction before it can be broadcast to the network. Multi-signature is commonly used in cryptocurrency and blockchain applications, where it is used to create a shared wallet that requires the signatures of multiple people before a transaction can be executed. This can provide an added layer of security and accountability, as it ensures that multiple people must agree before a transaction can be made. It is also used to create joint accounts, where multiple people can spend from the same account, but where a certain number of signatures are required before a transaction can be executed.