Unique ID for products on Amazon.
A parent ASIN is an Amazon ID assigned to a commodity product that combines multiple variations of the same product. It does not represent a specific product that can be purchased, but rather the general category to which the variations belong. For example, a shirt that comes in different sizes and colors would have a parent ASIN to group all of these variations together.
A child ASIN is an Amazon ID that is assigned to each specific variation of a product grouped under a parent ASIN. Each child ASIN represents a specific version of the product, for example, a shirt in size M and the color blue. It is the child ASIN that is used for transactions and inventory management for specific variations.
Situation where a losing seller is no longer the primary seller of the product concerned on Amazon.