A linked business account is a Revolut Business account that is connected to your Merchant Account.
If you have configured automatic withdrawals between a linked Revolut Business account and a Merchant Account, the available funds will be automatically transferred to your linked account at the end of each day. If your Merchant Account balance is too low, the linked business account will also be used to pay for refunds, chargebacks and fees.
You can select a linked business account associated with the Merchant Account by clicking on menu Settings of a particular Merchant Account.
For article about multi-business accounts, please see here.