What is sku in marketing?

Short for stock keeping unit, SKU is a unique numerical identifying number that refers to a specific stock item in a retailer's inventory or product catalog. The SKU is often used to identify the product, product size or type, and the manufacturer. In the retail industry, the SKU is a part of the backend inventory control system and enables a retailer to track a product in their inventory that may be in warehouses or in retail outlets.