A Retailer Is An Individual or Firm That Helps to Distribute a Product

Short Answer

A retailer is
an individual or firm that helps to distribute a product.
an intermediary who sells products to other businesses for resale to final consumers.
an intermediary who sells products directly to consumers.
a network of independent companies through which a product passes from producer to end-user.
the combination of distribution channels by which a firm gets its products to end-users.