A catalog is a collection of products. A shop operator creates products in the system, and creates one or more variants for each product. After this is done, the products are not yet visible to shoppers. To allow shoppers to see and order a product, the shop operator must first publish it to a catalog.
Currently, each shop has a single catalog.
Note: In the future, there may be many different catalogs per shop, for example, a spring and summer catalog, or catalogs per region. A catalog could in the future collect other things besides products, but currently only products are supported.