The Universal Product Code (UPC) is a barcode symbology (i.e., a specific type of barcode) that is widely used in the United States, Canada, the United Kingdom, Australia, New Zealand, and in other countries for tracking trade items in stores.ome retailers (clothing, furniture) do not use the GS1 System (other bar code symbologies, other article number systems). Other retailers use the EAN/UPC bar code symbology but without using a GTIN (for products brands sold at such retailers only).