The "shop in shop" retail concept is where a brand owner or retailer takes space in another retailer's store and fits it out to provide selling space dedicated to that secondary company's products.

A lot of brands/retailers have monobrand stores which are totally dedicated to their ranges e.g. Ponds, Sennheisers, Lakme etc; often they have "shop-in-shop" programs where they occupy a set amount of space in other multiple outlets, in addition to their monobrand stores.