Work In Process
Something that is being developed or suggested but that is not yet complete.
Work in progress includes goods that are partially completed, and are still in the production process. These are items that are mainly undergoing a certain process in the production cycle and are likely to be in-between places or different workstations.
The items that are currently Work in Progress do not include raw materials or finished goods. Work in Progress items, however, do not include raw materials or finished goods.
Work in Progress comprises of the full amount of raw materials that are required for a certain product because material listing and costing is carried out at the beginning of the production process.
Therefore, the total amount of work in progress, is, therefore, calculated as a mixture of the processes and raw materials that are already utilized, in addition to the materials and processes that are likely to be included.
https://dictionary.cambridge.org/ru/%D1%81%D0%BB%D0%BE%D0%B2%D0%B0%D1%80%D1%8C/%D0%B0%D0%BD%D0%B3%D0%BB%D0%B8%D0%B9%D1%81%D0%BA%D0%B8%D0%B9/work-in-progress
https://www.wikiaccounting.com/accounting-work-in-progress/
Richard Conway, William Maxwell, John O. McClain, L. Joseph Thomas, (1988) The Role of Work-in-Process Inventory in Serial Production Lines. Operations Research 36(2):229-241. http://dx.doi.org/10.1287/opre.36.2.229
https://www.sciencedirect.com/science/article/abs/pii/092552739290059G
https://smallbusiness.chron.com/calculate-ending-work-in-process-inventory-3196.html