What is a SKU?

A SKU is the internal name a business gives to a specific product variant so two people looking at a record can agree it's the same item. A red small t-shirt and a red medium t-shirt are different SKUs. Manufacturer barcodes (UPC, EAN) are global identifiers; SKUs are usually internal and reflect how the business thinks about its catalog. Where teams trip: SKU sprawl. A new size shows up, someone types a new code, and within a year there are three records for the same item with slight variations. The fix is naming discipline. Write a SKU format (brand-style-size-color works for most catalogs) and put one person in charge of renames, merges, and retirements. Without that, every report downstream becomes unreliable: inventory value, reorder, sales by item.