An association is a relation between one product to other products and groups.
The particularity of this relation (contrary to groups) is the direction (one-to-many).
An association has only a code and a localized label.
The association is typically used for creating Packs.
A pack is a product with its own properties, family, etc… Then, the product ‘pack’ has the same association with all products and (variant) groups contained in the pack.