GTIN stands for Global Trade Item Number, a unique identifier used to keep track of products and their variations across supply chains. There are several synonyms for GTIN, including UPC (Universal Product Code), EAN (European Article Number), ISBN (International Standard Book Number), and ASIN (Amazon Standard Identification Number). While each of these codes may have slight differences in their structure and use, they all serve the same purpose of helping retailers and manufacturers manage inventory and track sales data. With the rise of e-commerce, having accurate GTINs or their synonyms has become increasingly important for product listings and search optimizations.