Work in Process“Work in process” refers to manufactured inventory that has entered the production process but has not yet been completed. Related Articles:Top 25 Questions and Answers-Job Order Costing [With PDF]Free COGM CalculatorTop 30 Questions and Answers-Process Costing [With PDF]Top 8 Differences between Product Cost and Period Cost [Notes with PDF]There are many differences between product cost and period cost. The cost that can be directly assigned to a product is known as the product cost.