n. The ruddy duck, Erismatura rubida: so called from the steel-blue of the head, or perhaps for the same reason that it is called hardhead, hickory-head, and toughhead. See cut under Erismatura.n. The rainbow-trout, Salmo irideus. See cut under rainbow-trout.Tipped with steel.n. A large trout, Salmo rivularis, of the Pacific coast of the United States.