In business or commerce, an order is a stated intention, either spoken or written, to engage in a commercial transaction for specific products or services. From a buyer’s point of view it expresses the intention to buy and is called a purchase order. From a seller’s point of view it expresses the intention to sell and is referred to as a sales order. When the purchase order of the buyer and the sales order of the seller agree, the orders become a contract between the buyer and seller. Within an organization, the term order may be used to refer to a work order for manufacturing, a preventive maintenance order, or an order to make repairs to a facility. In many businesses, orders are used to collect and report costs and revenues according to well-defined purposes. Then it is possible to show for what purposes costs have been incurred.