A Global Trade Item Number (GTIN) is a numeric system that provides globally unique codes to identify goods, services, and trade items. More specifically, GTIN is a family of GS1 global data structures that employ 8, 12, 13, or 14 digits, and can be encoded into different types of data carriers. Right now, a GTIN is primarily used within barcodes, but it can also be used with other data carriers like radio frequency identification (RFID).
Since a GTIN is compatible with varying types of GS1 numbering strings, most companies in North America use the universal product code (UPC) as their form of GTIN.