Business Casual Stores are the places (and web sites) that actually sell business casual attire. These are typically different from the brands which simply design and market the clothing. Overall, there are many more business casual brands than stores that sell business casual clothing. Therfore, it is common at many stores such as department stores to find many business casual brands in the same place.
However, some brands also act as stores (retailers) and sell their own product. For instance, Banana Republic is both a brand and a store. It designs business casual clothing and then sells it from its own stores and web sites. On the other hand, Hugo Boss is solely a business casual brand. Hugo Boss designs and sell business casual attire, but then sell it through other stores such as Macy's, who do not design their own clothes.