Amazon Product Advertising API Developer's Manual page 477

SKU
UPC
variant
variation
Product Advertising API Developer Guide
Amazon.com and used/rare/collectable editions from fixed price MarketPlace
sellers.
(Stock Keeping Unit ) A merchant-specific identifier for a purchasable good, like
a shirt or chair. Amazon's version of the SKU is the ASIN.
(Universal Product Code) A 12-digit item identifier used in the US and CA locales.
The UPC is identifier used in barcodes.
A single version of a given product that has variations. A variant is an item defined
by its product, and the unique set of property values from each property in the
full set of required properties for that item.
Different versions of a given product. If a pair of pants is available in khaki and
olive, then the pants are said to have two variations. Variations are one of the
two types of product relationships we support (ensembles is the other).
API Version 2011-08-01
470