ASIN (Amazon Standard Identification Number)
ASINs are Amazon's product identifiers, distinct from UPC, EAN, or ISBN codes. New private-label products get a unique ASIN created at listing time; products already in Amazon's catalog (often via Amazon Catalog or matched from existing UPC) reuse the existing ASIN. Parent ASINs group variations (sizes, colors, packs); child ASINs are the variants themselves. Reverse-ASIN keyword tools (like Helium 10's Cerebro) use the ASIN as an input to extract the keywords a competing listing ranks for, making the ASIN the unit of competitive analysis on Amazon. ASINs persist even after a listing is deleted; reactivating a deleted ASIN sometimes recovers historical performance signal, sometimes not.