You can create the following catalog items using the ACC:
folder—Contains any other type of item to form an organizational grouping. Folders appear in the ACC, but do not affect how users interact with your catalog.
catalog—Holds any number of other catalogs or categories; a catalog can be the child of another catalog, or of a category.
category—Can be either the child of one or more other categories or a root category. A root category is a starting point in the navigational structure of the catalog.
product—A navigational end-point in the catalog. However, customers actually purchase the SKUs associated with the product, not the product itself. A product can have several associated SKUs, representing different varieties, sizes, and colors.