A supermarket, a large form of the traditional grocery store, is a self-service shop offering a wide variety of food and household products, organized into aisles. It is larger and has a wider selection than a traditional grocery store, but is smaller and more limited in the range of merchandise than a hypermarket or big-box market.

The supermarket typically comprises meat, fresh produce, dairy, and baked goods aisles, along with shelf space reserved for canned and packaged goods as well as for various non-food items such as kitchenware, household cleaners, pharmacy products and pet supplies. Some supermarkets also sell a variety of other household products that are consumed regularly, such as new condoms (where permitted), medicine, and clothes, and some stores sell a much wider range of non-food products: DVDs, sporting equipment, board games, and seasonal items (e.g., Christmas wrapping paper in December).

The traditional supermarket occupies a large amount of floor space, usually on a single level. It is usually situated near a residential area in order to be convenient to consumers. The basic appeal is the availability of a broad selection of goods under a single roof, at relatively low prices. Other advantages include ease of parking and frequently the convenience of shopping hours that extend into the evening or even 24 hours of day. Supermarkets usually allocate large budgets to advertising, typically through newspapers. They also present elaborate in-shop displays of products. The shops are usually part of corporate chains that own or control (sometimes by franchise) other supermarkets located nearby—even transnationally—thus increasing opportunities for economies of scale.

Supermarkets typically are supplied by the distribution centres of their parent companies, usually in the largest city in the area. Supermarkets usually offer products at relatively low prices by using their buying power to buy goods from manufacturers at lower prices than smaller stores can. They also minimise financing costs by paying for goods at least 30 days after receipt and some extract credit terms of 90 days or more from vendors. Certain products (typically staple foods such as bread, milk and sugar) are very occasionally sold as loss leaders, that is, with negative profit margins so as to attract shoppers to their store. There is some debate as to the effectiveness of this tactic. To maintain a profit, supermarkets make up for the lower margins by a higher overall volume of sales, and with the sale of higher-margin items bought by the intended higher volume of shoppers. Customers usually shop by placing their selected merchandise into shopping carts (trolleys) or baskets (self-service) and pay for the merchandise at the check-out. At present, many supermarket chains are attempting to further reduce labor costs by shifting to self-service check-out machines, where a single employee can oversee a group of four or five machines at once, assisting multiple customers at a time.

A larger full-service supermarket combined with a department store is sometimes known as a hypermarket. Other services offered at some supermarkets may include those of banks, cafés, childcare centres/creches, Insurance(and other financial services), Mobile Phone services, photo processing, video rentals, pharmacies and/or petrol stations.

History

n the early days of retailing, all products generally were fetched by an assistant from shelves behind the merchant's counter while customers waited in front of the counter and indicated the items they wanted. Also, most foods and merchandise did not come in individually wrapped consumer-sized packages, so an assistant had to measure out and wrap the precise amount desired by the consumer. This also offered opportunities for social interaction: many regarded this style of shopping as "a social occasion" and would often "pause for conversations with the staff or other customers."These practices were by nature very labor-intensive and therefore also quite expensive. The shopping process was slow, as the number of customers who could be attended to at one time was limited by the number of staff employed in the store.

Historically, there has been debate about the origin of the supermarket, with King Kullen and Ralphs of California having strong claims. Other contenders included Weingarten's Big Food Markets and Henke & Pillot. To end the debate, the Food Marketing Institute in conjunction with the Smithsonian Institution and with funding from H.J. Heinz, researched the issue. It defined the attributes of a supermarket as "self-service, separate product departments, discount pricing, marketing and volume selling."

It has been determined that the first true supermarket in the United States was opened by a former Kroger employee, Michael J. Cullen, on 4 August 1930, inside a 6,000-square-foot (560 m2) former garage in Jamaica, Queens in New York City. The store, King Kullen, operated under the slogan "Pile it high. Sell it low." At the time of Cullen's death in 1936, there were seventeen King Kullen stores in operation. Although Saunders had brought the world self-service, uniform stores and nationwide marketing, Cullen built on this idea by adding separate food departments, selling large volumes of food at discount prices and adding a parking lot.