A SKU is a unique code consisting of letters and numbers that identify characteristics about each piece of inventory, such as manufacturer, brand, style, color, and size.
Your company will issue your own unique SKU codes specific to the goods you sell. If you and your competitors are selling the same item, such as yoga pants, you will likely issue two different internal SKUs.
The purpose of SKUs is to help you more accurately and quickly account for every piece of your inventory.