waterfowl,  in the United States, all varieties of ducks, geese, and swans; the term is sometimes expanded to include some unrelated aquatic birds such as coots, grebes (see Slavonian, or horned, grebe (Podiceps auritus)Ingmar Holmasen), and loons. In Britain the term refers only to domesticated swans, geese, and ducks kept for ornamental purposes, wildfowl being the term used for wild birds of this group, especially in the context of shooting for sport. See also duck; goose; swan.