A term used by 19th-century English glassmakers to describe vessels with mold-blown vertical ribs but no corresponding indentations on the interior. This effect was achieved by partly inflating the gather, allowing it to cool sufficiently to become somewhat rigid, and then gathering an outer layer of glass around it. The parison was then further inflated in a ribbed dip mold, which shaped the soft outer layer without affecting the inner layer. The term is frequently but incorrectly applied to ancient Roman ribbed bowls, which were made in a different manner.