Accounts payable is a company's debt to its suppliers. When you purchase supplies from a supplier, you have to pay them back within a certain period of time. The amount of time that a company has before it accrues interest on those debts is called accounts payable days, and it's the amount of time that a company has to pay its suppliers before interest is accrued on those debts.

Source: https://aurorasoftwaresolution.wordpress.com/2022/09/08/how-your-small-business-can-benefit-from-accounts-payable-software-systems/