In the field of inventory management, a stock keeping unit
) is a distinct type of item for sale,
[William J. Sawaya, William C. Giauque, Production and operations management, Harcourt Brace Jovanovich, 1986, , p.122 "A stock-keeping unit, or sku is an individually identifiable item stored in a specific location and tracked by an inventory system."]
such as a product or service, and all attributes associated with the item type that distinguish it from other item types. For a product, these attributes could include manufacturer, description, material, size, color, packaging, and warranty terms. When a business takes inventory of its stock, it counts the quantity it has of each SKU.
SKU can also refer to a unique identifier or code that refers to the particular stock keeping unit. These codes are not regulated or standardized. When a company receives items from a vendor, it has a choice of maintaining the vendor's SKU or creating its own. This makes them distinct from Global Trade Item Number (GTIN), which are standard, global, tracking units. Universal Product Code (UPC), International Article Number (EAN), and Australian Product Number (APN) are special cases of GTINs.