A bookkeeping method that allocates a business's income and expenses to periods to which they apply, even though they haven't actually been received or paid. In this system, when you bill a customer, the amount is immediately reflected in your books as income, regardless of when the invoice is actually paid.
Accounts payable represent money your business owes to suppliers and other creditors at a given point in time. Accounts receivable are funds owed to you by customers and other debtors.
A period of time (month, quarter, year) for which a financial statement is produced.