- UPC: The Universal Product Code (UPC) is a bar code widely used to identify and track trade items in stores throughout the United States and Canada. The 12 digits of the code are all numeric and identify things like whether the item needs to be weighed for sale (think produce and meat) and what category of item the product occupies, like over-the-counter medicines.
- EAN: The European Article Number (EAN) is a bar-coding standard that is a subset of the original UPC from North America. This 13- digit number can also be called the Japanese Article Number.
- ISBN: The International Standard Book Number (ISBN) originated as a 9-digit number in the United Kingdom during the 1960s. It was then known as the Standard Book Number (SBN). In 1970, an additional digit was added and the code became the International SBN. It was developed by the International Organization for Standardization. As of January 1, 2007, there is also a 13-digit ISBN. A similar code, the International Standard Serial Number (ISSN), is for periodicals.
- ASIN: The Amazon Standard Identification Number (ASIN), unlike its companions, has no meaning outside of Amazon itself. It is a number issued by Amazon as an internal control number within the Amazon site. In the case of books, the ISBN is also the ASIN.
Of course, since not every product has all of those numbers, you might need to search by whatever keywords
you think are likely to pull up your product. Don't forget about other ways of optimizing your product listing