Electronic Point of Sales System. --Point of sale (also called POS or checkout, during computerization later becoming electronic point of sale or EPOS) is the place where a retail transaction is completed. It is the point at which a customer makes a payment to the merchant in exchange for goods or services. At the point of sale the retailer would calculate the amount owed by the customer and provide options for the customer to make payment. The merchant will also normally issue a receipt for the transaction. (Definition uproot from Wikipedia)