In modern conditions of the transformation of the provision of trade services and the networkization of the trade space, the need to consider the categorical apparatus of the essence of the service is predetermined. The article examines the existing foreign and domestic approaches to the essence of the service. The criteria for the formulation and consideration of the content of the service as a process, the result of the activity of a retail trade network are highlighted. The first scientific classical school of the categorical definition of a service is highlighted, which made it possible to highlight that the value of goods is manifested as an instrument of exchange for services. The considered approaches of a number of researchers who studied a service as a process or action. A number of definitions of modern authors are presented, who believe that a service is a work activity, expressed fully by a person's need. The connection of the service through the quality category is presented and the definition of the service as a component of the value chain of the retail trade network is clarified. In the conclusion, the conclusion is drawn that the service of the trading network is the result of activity.