This article does not have any sources. (July 2014)
According to  Oxford Dictionary, Retail is the sale of goods to the public in relatively small quantities for use or consumption rather than for resale.
For instance, when we buy shoes to wear or food to eat, we buy from a retailer.
Another way of purchasing retail items is by ordering them by mail, telephone, Internet or other methods, to be delivered by post or package delivery service such as United Parcel Service. Some items are sold door-to-door, in which a sales person goes to a possible customers home and tries to sell an item.