Global Trade Item Number
GTIN is a number assigned to a trade-able object. Developed by GS1, it resolves numbering schemes such as ISBN, ISMN, UPC, EAN, ISSN into a single "numbering space" so that scanners and databases that use the GTIN system can make use of these other numbering systems as well. This allows, for example, supermarket scanners to scan bar codes on paperback books that they might be selling. It also allows warehouses to scan cartons from publishers as well as chewing gum manufacturers. It's a way to allow for the efficient processing of products regardless of what vertical they happen to be from.