Accounts Receivable (AR)
Money earned but not yet paid
The money owed by customers to a business, normally represented by a series of invoices.
Accounts receivable or just "receivables" represents credit extended by a supplier. They normally have fixed terms that require payment to be made within a defined time period, ranging from a few days to a few months.
In the mobile business, AR is payments to the app publisher due from the app stores (Google and Apple), mobile ad networks, affiliate networks, etc. The delay in payment for these accounts receivables can be as long as 60 days from when the revenue was first earned.