商家 (shāngjiā) refers to a merchant, business, or store as a commercial entity — it's the seller side of a transaction. Unlike 商人 (shāngrén), which means a businessman as a person, 商家 is about the organization or shop. It's broader than 店铺 (diànpù, a physical store) and more concrete than 商业 (shāngyè, commerce as an abstract concept).