Accounts receivable

Accounts receivable is one of a series of accounting transactions dealing with the billing of customers who owe money to a person, company or organization for goods and services that have been provided to the customer. In most business entities this is typically done by generating an invoice and mailing or electronically delivering it to the customer which is to be paid within an established timeframe called credit or payment terms.
See more at Wikipedia.org...

Noun
1. a creditor's accounts of money owed to him; normally arise from the sale of products or services
(hypernym) assets

Money owed by customers.