A cost object is often a product or department for which costs are accumulated or measured. For example, a product is the cost object for direct materials, direct labor and manufacturing overhead. The factory maintenance department is a cost object for the cost of the maintenance employees and the maintenance supplies. Later the factory maintenance department costs will be assigned to products, which are also cost objects.
A cost object can also be a customer, a machine, a group of machines, a group of employees, etc.