Prawn is a common name for small aquatic crustaceans with an exoskeleton and ten legs (i.e. a member of the order decapoda), some of which can be eaten. The term prawn is used particularly in the United Kingdom, Ireland, and Commonwealth nations, for large swimming crustaceans or shrimp, especially those with commercial significance in the fishing industry. Shrimp that fall in this category often belong to the suborder Dendrobranchiata. In North America, the term is used less frequently, typically for freshwater shrimp. The terms shrimp and prawn themselves lack scientific standing. Over the years, the way shrimp and prawn are used has changed, and nowadays the terms are almost interchangeable.